Transmeta
Encyclopedia
Transmeta Corporation was a US-based corporation that licensed low power semiconductor intellectual property. Transmeta originally produced very long instruction word
code morphing
microprocessor
s, with a focus on reducing power consumption in electronic devices. It was founded in 1995 by Bob Cmelik, Dave Ditzel, Colin Hunter, Ed Kelly, Doug Laird, Malcolm Wing, and Greg Zyner. In January 2009, Transmeta was acquired by Novafora, which ceased operations in August 2009.
Transmeta produced two x86-compatible CPU architectures: Crusoe and Efficeon. These CPUs have appeared in subnotebook
s, notebook
s, desktop
s, blade server
s, tablet PC
s, a personal cluster computer, and a silent desktop, where low power consumption and heat dissipation are of primary importance.
Revenue for the third quarter of 2007 was $44 million, which included $43 million of services revenue and $1 million of license revenue for royalty payments.
. Transmeta attempted to staff the company in secret, although speculation online was not uncommon. One source of speculation was the company's bare-bones webpage. On November 12, 1999, a cryptic comment in the HTML appeared:
The company was largely successful in hiding its ambitions until the official announcement. Over 2000 non-disclosure agreement
s (NDAs) were signed during the stealth period.
Throughout Transmeta's first few years, little was known about exactly what it would be offering. Its web site went online in mid-1997, and for approximately two and a half years displayed nothing but the text "This web page is not yet here." Information gradually came out of the company, suggesting of a very long instruction word
-based (VLIW) design that translated x86 code into its own native code.
In fact, Transmeta marketed their microprocessor technology as extraordinarily innovative and revolutionary in the low-power market segment. They had hoped to be both power and performance leaders in the x86 space. But initial reviews of the Crusoe indicated the performance fell significantly short of projections. Also, during Crusoe development Intel and AMD significantly ramped up speeds and began to address increasing concerns about power consumption. So Crusoe was rapidly cornered into a low-volume, small form factor (SFF), low-power segment of the market.
In response, Transmeta quickly redesigned its technology, and produced the Efficeon processor. The Efficeon was claimed to have twice the performance of the original Crusoe CPU at the same frequency. But the performance was still weak relative to the competition, and the complexity of the chip had increased significantly. This greater size and power consumption may have diluted a key market advantage Transmeta's chips had previously enjoyed over the competition.
Transmeta has employed a number of industry luminaries such as Linus Torvalds
and Dave D. Taylor
. Initially, its purpose was kept secret, but partially because it had such talent amongst its staff, the industry was constantly abuzz with rumors in addition to 'conspiracy theories
' resulting in excellent press relations
(PR).
Torvalds left Transmeta in June 2003 to dedicate himself to the further development of the Linux kernel
.
As an example of technology media hype
, the company was once named as the Most important company in Silicon Valley in an Upside
magazine editorial. Less well reported was that the company was never profitable while it was a chip vendor. In 2002, it had a loss of $114 million dollars, in 2003 a loss of $88 million, in 2004 a loss of $107 million.
As of January 2005 the company announced a strategic restructuring away from being a chip product company to an intellectual property company. That is, instead of selling chips, it will sell technology for use by other chip makers. In February 2005, some speculated that AMD might buy Transmeta. In March 2005 Transmeta announced that it was laying off 68 people, leaving 208 employees. About half of the remaining employees were to work on propagating the LongRun2 power optimization technology within Sony products. Sony was reported to be a key licensee of this Transmeta technology.
Transmeta CEOs:
, not surpassed again until Google’s IPO in 2004. However, Transmeta had their first layoffs in July 2002, reducing the headcount of the company by 40%. On May 31, 2005, Transmeta announce the signing of asset purchase and license agreements with Hong Kong’s Culture.com Technology Limited. However, the deal fell apart due to delays in obtaining technology export licenses from the US Department of Commerce, and the parties announced the termination of the agreements on February 9, 2006. On August 10, 2005, Transmeta announced its first-ever profitable quarter. This was followed in 2006 by GameSpot
’s report on March 20 that Transmeta was working on an “unnamed” Microsoft
project. As it turned out, this was a secure platform under the AMD brand for Microsoft’s FlexGo program. On February 7, 2007, Transmeta closed its engineering services division, terminating 75 employees in the process. This was concurrent with an announcement that the company would no longer develop and sell hardware, but would focus on the development and licensing of intellectual property. Following this, AMD invested $7.5 million in Transmeta, planning to use the company’s patent portfolio in energy-efficient technologies. On August 8, 2008, Transmeta announced that it had licensed its LongRun and low-power chip technologies to Nvidia
for a one-time license fee of $25 million. Later in the year, on November 17, Transmeta announced the signing of a definitive agreement to be acquired by Novafora, a digital video processor company based in San Diego, CA, for $255.6 million in cash, subject to adjustments dependent on working capital. The deal was finalized on January 28, 2009, when Novafora announced the completion of its acquisition of Transmeta.
Intellectual Venture Funding LLC completed the acquisition of the patent portfolio formerly developed and owned by Transmeta Corporation on February 4, 2009.
Novafora collapsed in late July, 2009.
for infringement of ten Transmeta U.S. patents covering computer architecture and power efficiency technologies.
The complaint charged that Intel had infringed and was infringing Transmeta's patents by making and selling a variety of microprocessor products, including at least Intel's Pentium III, Pentium 4, Pentium M, Core and Core 2 product line.
On October 24, 2007, Transmeta announced an agreement to settle its lawsuit against Intel Corporation. Intel agreed to pay $150 million upfront and $20 million per year for five years to Transmeta in addition to dropping its counter-claims against Transmeta. Transmeta also agreed to license several of its patents and assign a small portfolio of patents to Intel as part of the deal.
(VLIW) cores. To execute x86 code, a pure software-based instruction translator dynamically compile
s or emulates x86 code sequences, using execution-hotspot guided heuristics. While similar technologies existed (Wabi for Solaris and Linux
, FX!32
for Alpha
and IA-32 EL
for Itanium
, open-source DAISY, the Mac 68K emulator
for the PowerPC) in the 1990s, the Transmeta approach has set a much higher bar for compatibility—able to execute all x86 instructions from initial boot up to the latest multimedia instructions—while retaining most of its core performance.
Transmeta trademarked the term "code-morphing" to describe their technology.
The operation of Transmeta's code-morphing systems software is very similar to the final optimisation pass of a conventional compiler. Considering a fragment of 32-bit x86 code:
addl %eax,(%esp) // load data from stack, add to %eax
addl %ebx,(%esp) // ditto, for %ebx
movl %esi,(%ebp) // load %esi from memory
subl %ecx,5 // subtract 5 from %ecx register
This is first converted simplistically into native instructions:
ld %r30,[%esp] // load from stack, into temporary
add.c %eax,%eax,%r30 // add to %eax, set condition codes.
ld %r31,[%esp]
add.c %ebx,%ebx,%r31
ld %esi,[%ebp]
sub.c %ecx,%ecx,5
The optimiser then eliminates common subexpressions and unnecessary condition code operations and, potentially, applies other optimisations such as loop unrolling:
ld %r30,[%esp] // load from stack only once
add %eax,%eax,%r30
add %ebx,%ebx,%r30 // reuse data loaded earlier
ld %esi,[%ebp]
sub.c %ecx,%ecx,5 // only this last condition code needed
Finally, the optimiser groups individual instructions ("atoms") into VLIW opcodes ("molecules") for the underlying hardware:
ld %r30,[%esp]; sub.c %ecx,%ecx,5
ld %esi,[%ebp]; add %eax,%eax,%r30; add %ebx,%ebx,%r30
These two VLIW opcodes will be executed in two clock cycles, as opposed to the larger number required for the original code executed on an x86 processor which did not perform complex optimisations in hardware.
Transmeta claims several technical benefits to this approach:
Prior to Crusoe's release, rumors indicated Transmeta was relying on these benefits to develop a hybrid PowerPC
and x86 processor. But Transmeta would initially concentrate solely on the extremely low-power x86 market.
The ability to quickly update products without a hardware respin was demonstrated in 2002 with an in-the-field upgrade (a download) to enhance CPU performance of the Crusoe
based HP Compaq TC1000
tablet PC. It was used again in 2004 when NX bit
and SSE3
support were added to the Efficeon
product line without requiring hardware changes. In the field upgrades were rare in practice due to system hardware vendors not wanting to incur additional customer support costs or spend additional money on QA for the potential upgrades or bug fixes to shipped products they had already closed the revenue books on.
.
Transmeta lost much credibility and endured significant criticism due to the poor initial Crusoe showing with large discrepancies between projections and actuals for both performance and power. Although power consumption was somewhat better than Intel and AMD offerings, the end user experience (i.e. battery life) only showed a marginal overall improvement. First, the Code Morphing Software
(CMS) combined with cache architecture artificially inflated comparisons between benchmarks and real-world applications. This is due to the repetitive nature of benchmarks and their small footprints. The CMS software overhead may have actually been a key cause of much lower performance for many real-world applications; the simple VLIW core architecture could not compete on computationally intensive applications; and the southbridge
interface was limited by its low bandwidth for graphics or other I/O-intensive applications. Some standard benchmarks even failed to run, throwing the claim of full x86 compatibility into doubt.
VLIW architecture), Efficeon stressed computational efficiency, low power consumption, and a low thermal footprint.
A 2004-model 1.6-GHz Transmeta Efficeon (manufactured using a 90-nm process) had roughly the same performance and power characteristics as a 1.6-GHz Intel Atom
from 2008 (manufactured using a 45-nm process). The Efficeon included an integrated Northbridge
, while the Atom requires an external Northbridge chip (reducing much of the Atom's power consumption benefits).
Subsequent "clean room" reverse engineering, published in 2004, clarifies some details of the native VLIW architecture and associated instruction set, and suggests that there are fundamental limitations that preclude porting an operating system such as Linux to it.
The same work also compares Transmeta's patented technology with prior art published and in some cases patented by IBM, and suggests that some claims might not stand detailed scrutiny.
processors, although, like AMD Opteron
processors, it supports a fully integrated memory controller
, a HyperTransport
IO bus, and the NX bit
, or no-execute x86 extension to PAE mode
. NX bit
support is available starting with CMS version 6.0.4.
Efficeon's computational performance relative to mobile CPUs like the Intel Pentium M
is thought to be lower, although little appears to be published about the relative performance of these competing processors.
Efficeon came in two package
types: a 783- and a 592-contact ball grid array
. Its power consumption was moderate (with some consuming as little as 3 watts at 1 GHz and 7 watts at 1.5 GHz), so it could be passively cooled.
Two generations of this chip were produced. The first generation (TM8600) was manufactured using a TSMC
130 nm process and produced at speeds up to 1.1 GHz
. The second generation (TM8800 and TM8820) was manufactured using a Fujitsu
90 nm process and produced at speeds ranging from 1 GHz to 1.7 GHz.
Internally, the Efficeon had two arithmetic logic unit
s, two load/store/add units, two execute units, two floating-point/MMX/SSE
/SSE2
units, one branch prediction unit, one alias unit, and one control unit. The VLIW core could execute a 256-bit VLIW instruction per cycle. A VLIW is called a molecule and has room to store eight 32-bit instructions (called atoms) per cycle.
The Efficeon had a 128-KB L1 instruction cache, a 64-KB L1 data cache and a 1-MB L2 cache. All caches were on die.
Additionally the Efficeon CMS (code morphing software) reserved a small portion of main memory (typically 32 MB) for its translation cache of dynamically translated x86 instructions.
processor addressed many of Crusoe's shortcomings and showed roughly a 2x real-world improvement over Crusoe. Its die was considerably smaller than Pentium 4 and Pentium M, when compared in the same process technology. Efficeon's die fabricated in 90 nm is 68 mm², which is 60% of the Pentium 4 in 90 nm, at 112 mm², with both processors possessing a 1 MB L2 cache.
The notion of selling a product into a specific thermal envelope was typically not understood by the mass of reviewers, who tended to compare Efficeon to the gamut of x86 microprocessors, regardless of power consumption or application. One such example of this criticism suggests the performance still significantly lagged Intel's Pentium M (Banias) and AMD's Mobile Athlon XP.
Very long instruction word
Very long instruction word or VLIW refers to a CPU architecture designed to take advantage of instruction level parallelism . A processor that executes every instruction one after the other may use processor resources inefficiently, potentially leading to poor performance...
code morphing
Code Morphing Software
Code Morphing Software is the technology used by Transmeta microprocessors to execute x86 instructions. In broad view, CMS reads x86 instructions and generates instructions for a proprietary VLIW processor, in the style of Shade...
microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
s, with a focus on reducing power consumption in electronic devices. It was founded in 1995 by Bob Cmelik, Dave Ditzel, Colin Hunter, Ed Kelly, Doug Laird, Malcolm Wing, and Greg Zyner. In January 2009, Transmeta was acquired by Novafora, which ceased operations in August 2009.
Transmeta produced two x86-compatible CPU architectures: Crusoe and Efficeon. These CPUs have appeared in subnotebook
Subnotebook
A subnotebook is a class of laptop computers that are smaller and lighter than a typical laptop....
s, notebook
Notebook
A notebook is a book or binder composed of pages of notes, often ruled, made out of paper, used for purposes including recording notes or memoranda, writing, drawing, and scrapbooking....
s, desktop
Desktop
Desktop refers to the surface of a desk.The term has been adopted as an adjective to distinguish office appliances which can be fitted on top of a desk, from larger equipment covering its own area on the floor....
s, blade server
Blade server
A blade server is a stripped down server computer with a modular design optimized to minimize the use of physical space and energy. Whereas a standard rack-mount server can function with a power cord and network cable, blade servers have many components removed to save space, minimize power...
s, tablet PC
Tablet computer
A tablet computer, or simply tablet, is a complete mobile computer, larger than a mobile phone or personal digital assistant, integrated into a flat touch screen and primarily operated by touching the screen...
s, a personal cluster computer, and a silent desktop, where low power consumption and heat dissipation are of primary importance.
Revenue for the third quarter of 2007 was $44 million, which included $43 million of services revenue and $1 million of license revenue for royalty payments.
History
The company began as a stealth startupStealth startup
A stealth startup is a startup company that avoids public attention. This may be done to hide information from competitors, or — as part of a marketing strategy — to manage public image....
. Transmeta attempted to staff the company in secret, although speculation online was not uncommon. One source of speculation was the company's bare-bones webpage. On November 12, 1999, a cryptic comment in the HTML appeared:
Yes, there is a secret message, and this is it:
Transmeta's policy has been to remain silent about its plans until it had something to demonstrate to the world.
On January 19th, 2000, Transmeta is going to announce and demonstrate what Crusoe processors can do.
Simultaneously, all of the details will go up on this Web site
for everyone on the Internet to see.
Crusoe will be cool hardware and software for mobile applications.
Crusoe will be unconventional, which is why we wanted to let you know in advance to come look at the entire Web site in January, so that you can get the full story and have access to all of the real details as soon as they are available.
The company was largely successful in hiding its ambitions until the official announcement. Over 2000 non-disclosure agreement
Non-disclosure agreement
A non-disclosure agreement , also known as a confidentiality agreement , confidential disclosure agreement , proprietary information agreement , or secrecy agreement, is a legal contract between at least two parties that outlines confidential material, knowledge, or information that the parties...
s (NDAs) were signed during the stealth period.
Throughout Transmeta's first few years, little was known about exactly what it would be offering. Its web site went online in mid-1997, and for approximately two and a half years displayed nothing but the text "This web page is not yet here." Information gradually came out of the company, suggesting of a very long instruction word
Very long instruction word
Very long instruction word or VLIW refers to a CPU architecture designed to take advantage of instruction level parallelism . A processor that executes every instruction one after the other may use processor resources inefficiently, potentially leading to poor performance...
-based (VLIW) design that translated x86 code into its own native code.
In fact, Transmeta marketed their microprocessor technology as extraordinarily innovative and revolutionary in the low-power market segment. They had hoped to be both power and performance leaders in the x86 space. But initial reviews of the Crusoe indicated the performance fell significantly short of projections. Also, during Crusoe development Intel and AMD significantly ramped up speeds and began to address increasing concerns about power consumption. So Crusoe was rapidly cornered into a low-volume, small form factor (SFF), low-power segment of the market.
In response, Transmeta quickly redesigned its technology, and produced the Efficeon processor. The Efficeon was claimed to have twice the performance of the original Crusoe CPU at the same frequency. But the performance was still weak relative to the competition, and the complexity of the chip had increased significantly. This greater size and power consumption may have diluted a key market advantage Transmeta's chips had previously enjoyed over the competition.
Transmeta has employed a number of industry luminaries such as Linus Torvalds
Linus Torvalds
Linus Benedict Torvalds is a Finnish software engineer and hacker, best known for having initiated the development of the open source Linux kernel. He later became the chief architect of the Linux kernel, and now acts as the project's coordinator...
and Dave D. Taylor
Dave D. Taylor
Dave D. Taylor is an American game programmer, best known as a former id Software employee and noted for his work promoting Linux gaming.In 1993 he graduated from University of Texas at Austin with a Bachelor of Science degree in electrical engineering....
. Initially, its purpose was kept secret, but partially because it had such talent amongst its staff, the industry was constantly abuzz with rumors in addition to 'conspiracy theories
Conspiracy theory
A conspiracy theory explains an event as being the result of an alleged plot by a covert group or organization or, more broadly, the idea that important political, social or economic events are the products of secret plots that are largely unknown to the general public.-Usage:The term "conspiracy...
' resulting in excellent press relations
Public relations
Public relations is the actions of a corporation, store, government, individual, etc., in promoting goodwill between itself and the public, the community, employees, customers, etc....
(PR).
Torvalds left Transmeta in June 2003 to dedicate himself to the further development of the Linux kernel
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
.
As an example of technology media hype
Media circus
Media circus is a colloquial metaphor, or idiom, describing a news event where the media coverage is perceived to be out of proportion to the event being covered, such as the number of reporters at the scene, the amount of news media published or broadcast, and the level of media hype...
, the company was once named as the Most important company in Silicon Valley in an Upside
Upside (magazine)
Upside was a San Francisco-based business and technology magazine for venture capitalists. It was published from 1989 to 2002. It had a circulation above 300,000.-Beginnings:Upside was started by banker Anthony B...
magazine editorial. Less well reported was that the company was never profitable while it was a chip vendor. In 2002, it had a loss of $114 million dollars, in 2003 a loss of $88 million, in 2004 a loss of $107 million.
As of January 2005 the company announced a strategic restructuring away from being a chip product company to an intellectual property company. That is, instead of selling chips, it will sell technology for use by other chip makers. In February 2005, some speculated that AMD might buy Transmeta. In March 2005 Transmeta announced that it was laying off 68 people, leaving 208 employees. About half of the remaining employees were to work on propagating the LongRun2 power optimization technology within Sony products. Sony was reported to be a key licensee of this Transmeta technology.
Transmeta CEOs:
- 1995 – 2001: David Ditzel
- 2001 – 2001: Mark Allen
- 2001 – 2002: Murray Godman & Hugh Barnes
- 2002 – 2005: Matt R. Perry
- 2005 – 2007: Art Swift
- 2007 – 2009: Lester Crudele
Timeline
After its founding in 1995, Transmeta and its goals remained largely unknown until its corporate launch on January 19, 2000. After their initial public offering at the price of $21/share, the value skyrocketed to an all time high of $50.26 before settling down to $46/share on opening day. This made Transmeta the last of the great high tech IPOs of the dot-com bubbleDot-com bubble
The dot-com bubble was a speculative bubble covering roughly 1995–2000 during which stock markets in industrialized nations saw their equity value rise rapidly from growth in the more...
, not surpassed again until Google’s IPO in 2004. However, Transmeta had their first layoffs in July 2002, reducing the headcount of the company by 40%. On May 31, 2005, Transmeta announce the signing of asset purchase and license agreements with Hong Kong’s Culture.com Technology Limited. However, the deal fell apart due to delays in obtaining technology export licenses from the US Department of Commerce, and the parties announced the termination of the agreements on February 9, 2006. On August 10, 2005, Transmeta announced its first-ever profitable quarter. This was followed in 2006 by GameSpot
GameSpot
GameSpot is a video gaming website that provides news, reviews, previews, downloads, and other information. The site was launched in May 1, 1996 by Pete Deemer, Vince Broady and Jon Epstein. It was purchased by ZDNet, a brand which was later purchased by CNET Networks. CBS Interactive, which...
’s report on March 20 that Transmeta was working on an “unnamed” Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
project. As it turned out, this was a secure platform under the AMD brand for Microsoft’s FlexGo program. On February 7, 2007, Transmeta closed its engineering services division, terminating 75 employees in the process. This was concurrent with an announcement that the company would no longer develop and sell hardware, but would focus on the development and licensing of intellectual property. Following this, AMD invested $7.5 million in Transmeta, planning to use the company’s patent portfolio in energy-efficient technologies. On August 8, 2008, Transmeta announced that it had licensed its LongRun and low-power chip technologies to Nvidia
NVIDIA
Nvidia is an American global technology company based in Santa Clara, California. Nvidia is best known for its graphics processors . Nvidia and chief rival AMD Graphics Techonologies have dominated the high performance GPU market, pushing other manufacturers to smaller, niche roles...
for a one-time license fee of $25 million. Later in the year, on November 17, Transmeta announced the signing of a definitive agreement to be acquired by Novafora, a digital video processor company based in San Diego, CA, for $255.6 million in cash, subject to adjustments dependent on working capital. The deal was finalized on January 28, 2009, when Novafora announced the completion of its acquisition of Transmeta.
Intellectual Venture Funding LLC completed the acquisition of the patent portfolio formerly developed and owned by Transmeta Corporation on February 4, 2009.
Novafora collapsed in late July, 2009.
Lawsuit against Intel Corporation
On October 11, 2006, Transmeta announced that they had filed a lawsuit against Intel CorporationIntel Corporation
Intel Corporation is an American multinational semiconductor chip maker corporation headquartered in Santa Clara, California, United States and the world's largest semiconductor chip maker, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most...
for infringement of ten Transmeta U.S. patents covering computer architecture and power efficiency technologies.
The complaint charged that Intel had infringed and was infringing Transmeta's patents by making and selling a variety of microprocessor products, including at least Intel's Pentium III, Pentium 4, Pentium M, Core and Core 2 product line.
On October 24, 2007, Transmeta announced an agreement to settle its lawsuit against Intel Corporation. Intel agreed to pay $150 million upfront and $20 million per year for five years to Transmeta in addition to dropping its counter-claims against Transmeta. Transmeta also agreed to license several of its patents and assign a small portfolio of patents to Intel as part of the deal.
Technology
The actual Transmeta processors are in-order very long instruction wordVery long instruction word
Very long instruction word or VLIW refers to a CPU architecture designed to take advantage of instruction level parallelism . A processor that executes every instruction one after the other may use processor resources inefficiently, potentially leading to poor performance...
(VLIW) cores. To execute x86 code, a pure software-based instruction translator dynamically compile
Compile
Compile may refer to:* Compile , a Japanese video game company founded in 1983 that specialized in shoot 'em up and computer puzzle game genres...
s or emulates x86 code sequences, using execution-hotspot guided heuristics. While similar technologies existed (Wabi for Solaris and Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
, FX!32
FX!32
FX!32 is a software emulator program that allows x86 Win32 programs to execute on Alpha-based systems running Windows NT. Released in 1996, FX!32 was developed by Digital Equipment Corporation to support their Alpha microprocessors...
for Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
and IA-32 EL
IA-32 Execution Layer
The IA-32 Execution Layer is a software emulator in the form of a software driver that improves performance of 32-bit applications running on 64-bit Intel Itanium-based systems, particularly those running Linux and Windows Server 2003...
for Itanium
Itanium
Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...
, open-source DAISY, the Mac 68K emulator
Mac 68K emulator
The Mac 68K emulator was a software emulator built into all versions of the Mac OS for PowerPC. This emulator permitted the running of applications and system code that were originally written for the 680x0 based Macintosh models. The emulator was completely seamless for users, and reasonably...
for the PowerPC) in the 1990s, the Transmeta approach has set a much higher bar for compatibility—able to execute all x86 instructions from initial boot up to the latest multimedia instructions—while retaining most of its core performance.
Transmeta trademarked the term "code-morphing" to describe their technology.
The operation of Transmeta's code-morphing systems software is very similar to the final optimisation pass of a conventional compiler. Considering a fragment of 32-bit x86 code:
addl %eax,(%esp) // load data from stack, add to %eax
addl %ebx,(%esp) // ditto, for %ebx
movl %esi,(%ebp) // load %esi from memory
subl %ecx,5 // subtract 5 from %ecx register
This is first converted simplistically into native instructions:
ld %r30,[%esp] // load from stack, into temporary
add.c %eax,%eax,%r30 // add to %eax, set condition codes.
ld %r31,[%esp]
add.c %ebx,%ebx,%r31
ld %esi,[%ebp]
sub.c %ecx,%ecx,5
The optimiser then eliminates common subexpressions and unnecessary condition code operations and, potentially, applies other optimisations such as loop unrolling:
ld %r30,[%esp] // load from stack only once
add %eax,%eax,%r30
add %ebx,%ebx,%r30 // reuse data loaded earlier
ld %esi,[%ebp]
sub.c %ecx,%ecx,5 // only this last condition code needed
Finally, the optimiser groups individual instructions ("atoms") into VLIW opcodes ("molecules") for the underlying hardware:
ld %r30,[%esp]; sub.c %ecx,%ecx,5
ld %esi,[%ebp]; add %eax,%eax,%r30; add %ebx,%ebx,%r30
These two VLIW opcodes will be executed in two clock cycles, as opposed to the larger number required for the original code executed on an x86 processor which did not perform complex optimisations in hardware.
Transmeta claims several technical benefits to this approach:
- As the market leaders IntelIntel CorporationIntel Corporation is an American multinational semiconductor chip maker corporation headquartered in Santa Clara, California, United States and the world's largest semiconductor chip maker, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most...
and/or AMDAdvanced Micro DevicesAdvanced Micro Devices, Inc. or AMD is an American multinational semiconductor company based in Sunnyvale, California, that develops computer processors and related technologies for commercial and consumer markets...
would extend the core x86 instruction set, Transmeta could quickly upgrade their product with a software upgrade rather than requiring a respin of their hardware. This method just emphasises the compatibility rather than the performance. - Performance and power can be tuned in software to meet market needs.
- It would be relatively simple to fix hardware design or manufacturing flaws in the hardware using software workaroundWorkaroundA workaround is a bypass of a recognized problem in a system. A workaround is typically a temporary fix that implies that a genuine solution to the problem is needed...
s. - More time could be spent concentrating on enhancing the capabilities of the core or reducing its power consumption without worrying about 33 years of backward compatibility to the x86 architecture.
- The processor could emulate multiple other architectures, possibly even at the same time. (At its initial Crusoe launch, Transmeta demonstrated pico-Java and x86 running intermixed on the native hardware.)
Prior to Crusoe's release, rumors indicated Transmeta was relying on these benefits to develop a hybrid PowerPC
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...
and x86 processor. But Transmeta would initially concentrate solely on the extremely low-power x86 market.
The ability to quickly update products without a hardware respin was demonstrated in 2002 with an in-the-field upgrade (a download) to enhance CPU performance of the Crusoe
Transmeta Crusoe
The Crusoe is a family of x86-compatible microprocessors developed by Transmeta. Crusoe was notable for its method of achieving x86 compatibility. Instead of the instruction set architecture being implemented in hardware, or translated by specialized hardware, the Crusoe runs a software abstraction...
based HP Compaq TC1000
Compaq TC1000
The TC1000 is a hybrid Tablet PC designed by Compaq, before it was purchased by HP. It used the Transmeta Crusoe processor. Unlike many Tablet PCs which can only operate either in traditional laptop configuration, or with the keyboard folded behind the screen, the display is fully detachable from...
tablet PC. It was used again in 2004 when NX bit
NX bit
The NX bit, which stands for No eXecute, is a technology used in CPUs to segregate areas of memory for use by either storage of processor instructions or for storage of data, a feature normally only found in Harvard architecture processors...
and SSE3
SSE3
SSE3, Streaming SIMD Extensions 3, also known by its Intel code name Prescott New Instructions , is the third iteration of the SSE instruction set for the IA-32 architecture. Intel introduced SSE3 in early 2004 with the Prescott revision of their Pentium 4 CPU...
support were added to the Efficeon
Efficeon
The Efficeon processor is Transmeta's second-generation 256-bit VLIW design which employs a software engine to convert code written for x86 processors to the native instruction set of the chip...
product line without requiring hardware changes. In the field upgrades were rare in practice due to system hardware vendors not wanting to incur additional customer support costs or spend additional money on QA for the potential upgrades or bug fixes to shipped products they had already closed the revenue books on.
Crusoe
Crusoe was the first family of microprocessors from Transmeta, named after the literary character Robinson CrusoeRobinson Crusoe
Robinson Crusoe is a novel by Daniel Defoe that was first published in 1719. Epistolary, confessional, and didactic in form, the book is a fictional autobiography of the title character—a castaway who spends 28 years on a remote tropical island near Trinidad, encountering cannibals, captives, and...
.
Transmeta lost much credibility and endured significant criticism due to the poor initial Crusoe showing with large discrepancies between projections and actuals for both performance and power. Although power consumption was somewhat better than Intel and AMD offerings, the end user experience (i.e. battery life) only showed a marginal overall improvement. First, the Code Morphing Software
Code Morphing Software
Code Morphing Software is the technology used by Transmeta microprocessors to execute x86 instructions. In broad view, CMS reads x86 instructions and generates instructions for a proprietary VLIW processor, in the style of Shade...
(CMS) combined with cache architecture artificially inflated comparisons between benchmarks and real-world applications. This is due to the repetitive nature of benchmarks and their small footprints. The CMS software overhead may have actually been a key cause of much lower performance for many real-world applications; the simple VLIW core architecture could not compete on computationally intensive applications; and the southbridge
Southbridge (computing)
The southbridge is one of the two chips in the core logic chipset on a personal computer motherboard, the other being the northbridge. The southbridge typically implements the slower capabilities of the motherboard in a northbridge/southbridge chipset computer architecture. In Intel chipset...
interface was limited by its low bandwidth for graphics or other I/O-intensive applications. Some standard benchmarks even failed to run, throwing the claim of full x86 compatibility into doubt.
Efficeon
The Efficeon processor was Transmeta's second-generation 256-bit VLIW processor design. Like the Crusoe (a 128-bit128-bit
There are currently no mainstream general-purpose processors built to operate on 128-bit integers or addresses, though a number of processors do operate on 128-bit data. The IBM System/370 could be considered the first rudimentary 128-bit computer as it used 128-bit floating point registers...
VLIW architecture), Efficeon stressed computational efficiency, low power consumption, and a low thermal footprint.
A 2004-model 1.6-GHz Transmeta Efficeon (manufactured using a 90-nm process) had roughly the same performance and power characteristics as a 1.6-GHz Intel Atom
Intel Atom
Intel Atom is the brand name for a line of ultra-low-voltage x86 and x86-64 CPUs from Intel, designed in 45 nm CMOS and used mainly in netbooks, nettops, embedded application ranging from health care to advanced robotics and Mobile Internet devices...
from 2008 (manufactured using a 45-nm process). The Efficeon included an integrated Northbridge
Northbridge (computing)
The northbridge has historically been one of the two chips in the core logic chipset on a PC motherboard, the other being the southbridge. Increasingly these functions have migrated to the CPU chip itself, beginning with memory and graphics controllers. For Intel Sandy Bridge and AMD Fusion...
, while the Atom requires an external Northbridge chip (reducing much of the Atom's power consumption benefits).
Native VLIW
In principle, it should be possible to optimise x86 code to favour code-morphing software, or even for compilers to target the native VLIW architecture directly. However, writing in 2003, Linus Torvalds apparently dismissed these approaches as unrealistic:Subsequent "clean room" reverse engineering, published in 2004, clarifies some details of the native VLIW architecture and associated instruction set, and suggests that there are fundamental limitations that preclude porting an operating system such as Linux to it.
The same work also compares Transmeta's patented technology with prior art published and in some cases patented by IBM, and suggests that some claims might not stand detailed scrutiny.
Implementation
In conjunction with its code-morphing software the Efficeon most closely mirrors the feature set of Intel Pentium 4Pentium 4
Pentium 4 was a line of single-core desktop and laptop central processing units , introduced by Intel on November 20, 2000 and shipped through August 8, 2008. They had a 7th-generation x86 microarchitecture, called NetBurst, which was the company's first all-new design since the introduction of the...
processors, although, like AMD Opteron
Opteron
Opteron is AMD's x86 server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture . It was released on April 22, 2003 with the SledgeHammer core and was intended to compete in the server and workstation markets, particularly in the same...
processors, it supports a fully integrated memory controller
Memory controller
The memory controller is a digital circuit which manages the flow of data going to and from the main memory. It can be a separate chip or integrated into another chip, such as on the die of a microprocessor...
, a HyperTransport
HyperTransport
HyperTransport , formerly known as Lightning Data Transport , is a technology for interconnection of computer processors. It is a bidirectional serial/parallel high-bandwidth, low-latency point-to-point link that was introduced on April 2, 2001...
IO bus, and the NX bit
NX bit
The NX bit, which stands for No eXecute, is a technology used in CPUs to segregate areas of memory for use by either storage of processor instructions or for storage of data, a feature normally only found in Harvard architecture processors...
, or no-execute x86 extension to PAE mode
Physical Address Extension
In computing, Physical Address Extension is a feature to allow x86 processors to access a physical address space larger than 4 gigabytes....
. NX bit
NX bit
The NX bit, which stands for No eXecute, is a technology used in CPUs to segregate areas of memory for use by either storage of processor instructions or for storage of data, a feature normally only found in Harvard architecture processors...
support is available starting with CMS version 6.0.4.
Efficeon's computational performance relative to mobile CPUs like the Intel Pentium M
Pentium M
The Pentium M brand refers to a family of mobile single-core x86 microprocessors introduced in March 2003 , and forming a part of the Intel Carmel notebook platform under the then new Centrino brand...
is thought to be lower, although little appears to be published about the relative performance of these competing processors.
Efficeon came in two package
Package
Package can refer to:* Packaging and labeling* Package testing* Mail item larger than a letter* Chip package or chip carrier, in electronics, the material added around a component or integrated circuit to allow it to be handled without damage and incorporated into a circuit* Automotive package, in...
types: a 783- and a 592-contact ball grid array
Ball grid array
A ball grid array is a type of surface-mount packaging used for integrated circuits.- Description :The BGA is descended from the pin grid array , which is a package with one face covered with pins in a grid pattern. These pins conduct electrical signals from the integrated circuit to the printed...
. Its power consumption was moderate (with some consuming as little as 3 watts at 1 GHz and 7 watts at 1.5 GHz), so it could be passively cooled.
Two generations of this chip were produced. The first generation (TM8600) was manufactured using a TSMC
TSMC
Taiwan Semiconductor Manufacturing Company, Limited or TSMC is the world's largest dedicated independent semiconductor foundry, with its headquarters and main operations located in the Hsinchu Science Park in Hsinchu, Taiwan.-Overview:...
130 nm process and produced at speeds up to 1.1 GHz
GHZ
GHZ or GHz may refer to:# Gigahertz .# Greenberger-Horne-Zeilinger state — a quantum entanglement of three particles.# Galactic Habitable Zone — the region of a galaxy that is favorable to the formation of life....
. The second generation (TM8800 and TM8820) was manufactured using a Fujitsu
Fujitsu
is a Japanese multinational information technology equipment and services company headquartered in Tokyo, Japan. It is the world's third-largest IT services provider measured by revenues....
90 nm process and produced at speeds ranging from 1 GHz to 1.7 GHz.
Internally, the Efficeon had two arithmetic logic unit
Arithmetic logic unit
In computing, an arithmetic logic unit is a digital circuit that performs arithmetic and logical operations.The ALU is a fundamental building block of the central processing unit of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers...
s, two load/store/add units, two execute units, two floating-point/MMX/SSE
Streaming SIMD Extensions
In computing, Streaming SIMD Extensions is a SIMD instruction set extension to the x86 architecture, designed by Intel and introduced in 1999 in their Pentium III series processors as a reply to AMD's 3DNow! . SSE contains 70 new instructions, most of which work on single precision floating point...
/SSE2
SSE2
SSE2, Streaming SIMD Extensions 2, is one of the Intel SIMD processor supplementary instruction sets first introduced by Intel with the initial version of the Pentium 4 in 2001. It extends the earlier SSE instruction set, and is intended to fully supplant MMX. Intel extended SSE2 to create SSE3...
units, one branch prediction unit, one alias unit, and one control unit. The VLIW core could execute a 256-bit VLIW instruction per cycle. A VLIW is called a molecule and has room to store eight 32-bit instructions (called atoms) per cycle.
The Efficeon had a 128-KB L1 instruction cache, a 64-KB L1 data cache and a 1-MB L2 cache. All caches were on die.
Additionally the Efficeon CMS (code morphing software) reserved a small portion of main memory (typically 32 MB) for its translation cache of dynamically translated x86 instructions.
Reception
The EfficeonEfficeon
The Efficeon processor is Transmeta's second-generation 256-bit VLIW design which employs a software engine to convert code written for x86 processors to the native instruction set of the chip...
processor addressed many of Crusoe's shortcomings and showed roughly a 2x real-world improvement over Crusoe. Its die was considerably smaller than Pentium 4 and Pentium M, when compared in the same process technology. Efficeon's die fabricated in 90 nm is 68 mm², which is 60% of the Pentium 4 in 90 nm, at 112 mm², with both processors possessing a 1 MB L2 cache.
The notion of selling a product into a specific thermal envelope was typically not understood by the mass of reviewers, who tended to compare Efficeon to the gamut of x86 microprocessors, regardless of power consumption or application. One such example of this criticism suggests the performance still significantly lagged Intel's Pentium M (Banias) and AMD's Mobile Athlon XP.