Q1. How often have you misplaced your car key? (Be honest now..)
Never.
Q2. How often have you accidently locked a car, whle the keys were in it? (Remember - honest answers, now..)
Never.
QA. How often have you ever forgoten a pasword?
QB. How often (exactly) have you personally lost/had a computer stolen, and still cared more about whether or not the processor sill worked than your data?
Gratefully, I've never had such a thing happen, but the data has always been worth waaay more than the computer.
Add up sum from answers Q1 & Q2, subtract number of times QB is applicable, multiply resulting number by QA & the number of days to Christmas (In the Year 2525), then....boycott this (and every other) backdoor BS, seriously.
I have always locked doors with the key. ("always" == every single time I've locked a door, it was done with the key. I often don't bother to lock my friendly old car.)
I have an IronKey® and did in fact forget the password to it, for the first 7 of 10 tries. Fortunately I finally remembered it and still have use of it.
My wife's psychology business requires us to keep our equipment under lock and key, so we do. I am adding additional crypto layers as we speak, just to make sure. I don't think it's worth trying to prevent NSA-quality spying on my wife's patient appointment records, but your average cracker should have a pretty difficult time with it. Remote disable is far less interesting to me than good security policy.
Joking aside, I will not voluntarily depend on a device that can be easily disabled remotely. Yes, I have an Android® phone, and no I don't depend on it.
The sequel was, in my opinion, as interesting as the original novel. Jones delved into some uncomfortable social (to me) territory, then finished up with a nice Faustian twist. (Damn, I read the *sequel* 35 years ago.... where DOES the time go?)
just imagine how much it's going to cost when oil rig employees have to be compensated well enough to offset not only the risk of death but also imprisonment at the hands of an angry mob
Citation required.
So far as I've read and seen on this disaster, not one word has been spoken of or about the oil rig employees, other than ones who got their asses killed because "accidents happen". I have read and seen multiple reports about multiple failures by decisionmakers to cut corners in an enterprise whose risks are significant and (if not precisely known) are legendary. Worse, the costs of failure in this particular enterprise are massive and ongoing dislocation of large numbers of people whose productive lives depend on the gulf of Mexico.
So you have tried to twist an argument about decisionmakers behaving in a criminally negligent way, into personal risk of oil rig employees facing an angry mob.
It is an invalid and in my opinion irresponsible argument.
I've read your comments in other threads and you are both smarter and wiser than this.
... retirement with resources that would serve as comfortable retirement packages for, I'm guessing, 100 middle-class families.
Every time I hear this bullshit about the board serving stockholders and the CEO serving the board, I remember that they tend to downsize from 6 yachts to 4, and from 6 chalets to 2.
And we have politicians running for office in the upcoming U.S. elections demanding that "the government get its boot heel off BP's throat".
This is how we treat those whose decisions lead to catastrophic consequences for society and the people who actually have to work for a living. Drop their $200 million retirement package all the way down to $130 million. Tough shit for those executives.
I am old enough to remember the oil shocks of the 70's and the national response to them. People thought a little bit about efficiency, and for a few years demanded research funding on alternatives. The result was a 25% (or so) drop in demand for "oil" and its derivatives. Those events pissed off the top executives, so they began a comprehensive and sustained war against any credible replacement of their product, or even for ways to dilute their market power.
I have been thinking about what you are saying here for 30 years.
Every single year it's the same damn story: "Don't touch our energy supply! It will destroy the economy!"
Not once have I heard anyone with real influence say something new like "We should really be researching how to manage a transition away from what appears to be a limited, environmentally risky, and internationally de-stabilizing energy supply."
The incumbents (oil execs, etc.) have succeeded in preventing this society from even trying to figure out how to be economically viable if/when it becomes necessary to move beyond petroleum. So now we have people noting (unfortunately correctly) how dependent we are on the decisions of between 60 and 200 boards of directors of the major energy companies.
All that talk about "the market" is totally fucking bogus. The fact is that all of western society is stuck with the planning decisions of those executives. I hear libertarians and conservatives talk about the government all the time talking about "private industry" having the "freedom to innovate".
Sorry guys, those executives and a few others (the top few banking institutions, the top few media companies, etc.) are basically running things exactly the way the planned economies of yore were run, with the same effects: An absolutely perfect record of failure to manage change effectively.
The people directing the energy industry have been careful to prevent significant research into alternatives to their product for *decades*.
I am bloody tired of hearing the strawman argument that says "we cannot move away from oil today, so don't do a goddamned thing about what may be a looming economic problem in the near future!". Nobody is saying "drop all oil all at once immediately". Some people are saying, "Let's get moving on methods, practices and technologies that reduce our dependence on a resource that destabilizes world politics (it's already difficult enough even without the perversions of energy supply management), and which evidently can fuck over entire regions of ocean, shoreline, etc.
The major oil companies have had their lobbying industry working overtime for 40 years to preserve their status as the most important players in an industry that that influences every other major economic activity.
To summarize: It is way past time to begin looking seriously for ways and means for delivering the capabilities that oil has provided historically. And the pussies who are afraid to compete in an truly open marketplace where they don't own a major fraction of our infrastructure can just shut the fuck up, they've had their run and it's time to re-establish a properly competitive marketplace for energy.
As far as I've been able to tell during 40 years of watching and reading, the change that wold be most beneficial to most people in society is the single most important characteristic of alternative sources as they are currently conceived: Decentralization of supply and consequently loss of control over this critical component of our infrastructure.
Under NO CIRCUMSTANCES will the major oil companies allow the growth of technologies that reduce their influence on our energy supply. As long as "oil" and "coal" remain highly capitalized and highly centralized their managers/executives have influence over the choices our society makes due to their control over a large fraction of our energy supply, they are pulling in major profits both as companies and as individual major stock holders.
The central tenet of net neutrality is, get ready for it....
neutrality
No corporate executive dictation.
You may or may not be old enough to remember the days before internet freedom, when there was a *MAJOR* toll to be paid by anyone wishing to cross the boundaries established by manufacturers (Hello, IBM of the '70's) or providers (hello, AT&T before Carterfone) or postal/telegraph monopolies (hello, old Europe).
Then came along a non-encumbered, free and open internet.
???
Piles and SHITLOADS of profit, growing every day. Providing room for anyone with the willingness and ability to compete openly and freely.
Net neutrality is, by definition, freedom: The free flow of information among those who would exchange it, independent of corporate desire to limit that freedom.
I thought it was reasonably well understood that one of Walmart's primary characteristics is their *amazing* control over logistics. In fact, I thought one of their big process inventions was to bring logistical activity online.
I welcome clarification, since I haven't worked for Walmart.
...is easier than writing it using 1970s technology in assembly
Been there, done that: Assembly, FORTRAN (II, IV, V), COBOL, PL/1. (I remember when DB2 rented for several grand per month.)
Developing has gotten way more easier, though what I've found is that the expectations are way more greater [sic]. Many experiments have died on the vine, but as you note, we needed those experiments to find the right solutions.
Anyone that thinks that relational databases are the end-all-be-all of persistent data storage hasn't done enough relational database development to understand some of the limitations.
Our development organization is heavily invested in PostgreSQL, finding it to be perfectly matched to almost all of our needs. It is exceptionally reliable, and is very (but not perfectly) manageable. (We've had issues in the past with mis-timed auto-VACUUM for instance which are now resolved.) We even found a small but significant corner-case bug which upon being reported, received immediate attention from the developers, resulting in a resolution in under 72 hours. I believe our use of this particular tool has saved us significant resources (dollars, developer time) that has allowed the development organization to direct our time and money to our own application development.
But we're finding that even PostgreSQL has limits, mostly with respect to the large and growing datasets our application uses for large scale real time control. We could transition to a really expensive SQL solution, but we are at least considering the choices that may be a better fit for these particular subsystems than PostgreSQL or any other SQL solution. Just a few weeks ago, we started seeing a good comment in teh interWebs... "NoSQL" should mean "not only SQL".
Not a rejection of a powerful toolkit that holds a central role in our organization, but rather a recognition that we would be remiss in our responsibilities if we didn't pay attention to the choices that could simplify our lives as developers.
Being happily ensconced in the bare metal world (Cortex-M3: Nice machine), I would be careful about using the word "inferior".One starts to count bytes and k's when the *entire system cost* is under $25.00 including power supplies.
With that being said, most embedded developers do the bulk of their work in C and on occasion C++ (with great care), with very little assembly support. For what it's worth, most CPU developers are aware of the transition to C and have done an excellent job of making it possible to do almost all system management, including exceptions/faults/priority/interrupts, in C with very little ASM. Where ASM does become necessary, it's usually expressed in a function-call form that keeps the C code neat and clean.
Heh. I ran many of my CS projects on the PDP-8L in an Industrial Engineering lab rather than the IBM 370/168 upstairs.
I used a Fortran IV compiler whose compiled output was intended to run directly on add-on floating point hardware. DEC had a floating point emulator for us poor folks so I ran my projects in a virltualized environment on an 8 kword PDP-8L in 1976.
Upstairs the rich guys with computing center accounts (time was so expensive that one needed authorization to use a real computer) could use either CMS or VM/370 interactively, or OS/MVT. I believe the 370 had the add-on dynamic address translation hardware but cannot prove it.
Back then, people were exceptionally territorial with their systems and permission to use them.
... using RSX emulation. I can no longer remember the compiler we used . Maybe Whitesmiths? But I do remember needing to implement a really basic:-) stdio library.
By the time we were finished with the project, we had implemented a client-server data management system (it could not be called a database) that supported transactions, ordered indexes and never lost a record through years of operation.
The company ended up replacing a PDP-11/73 with a SparcServer 2 in 1990, I think.
We're using the downloadable version of the Code Sourcery toolchain, to which we were directed by Atmel. FWIW, (IMHO) Code Sourcery has done a good job of collecting the often disparate components that make up a good toolchain.
I am operating under a basic assumption that converting from an old-school 8-bitter to the CortexM3 is guaranteed to take some careful thinking, planning and verification using various tools (particularly including objdump!)...
I'll check back occasionally to see if you have further questions; since I'm in the early stages of this porting process, I have plenty of questions and welcome additional thoughts.
Sorry about the late response, I've been tracking down endianness, packing and crypto issues in the comms layer of this porting job.
Not to sound disagreeable, I had exactly the attitude you describe. But having been convinced (OK, forced) to develop for a Cortex-M3 (thumb-2 ONLY) part, I've become convinced that the thumb-2 instruction set is actually very good. It offers excellent code density, while still allowing me to code "just the way I want". I have checked several basic routines that we depend on for our work, and as far as I am concerned, the ARM guys have hit the sweet spot for the work we're doing in our embedded project.
I checked a fair amount of bit-twiddling functionality, including CRC-16 (big and little-endian), a few basic crypto functions, and general structure access.
Though not specifically related to thumb-2 "cruft", I believe another significant improvement in the ARM approach is that they have built an excellent stack/exception entry and return model that does a surprisingly good job of reducing our dependence on assembly language escapes or functions. Almost the entire processor, peripheral blocks, system control initialization is done in C with the contribution of a few ASM escapes that are coded to behave as ordinary functions. In the cortex world, ARM refers to this as "CMSIS", the "cortex Microcontroller Software Interface Standard".
I am porting an IEEE 802.15.4 (physical layer compatibility only, proprietary protocol) system from an old school 8/16 bit CPU to a cortex-M3 (Atmel AT91SAM3U4) right now. Having been coded on the byte-wide machine, all sorts of protocol structures have odd alignments.
I have verified that the new CPU is tolerant of unaligned accesses, both of shorts on odd boundaries and longs on both odd byte and odd-halfword boundaries. Forcing GCC to compile the "unnatural" packing requires the use of an attribute:
typedef struct {
unsigned char uc1;
unsigned int ui1 __attribute__((packed));
unsigned short us1 __attribute__((packed)); } Pstruct;
(I am typing this from memory, it may not be just right but should communicate the basic idea.)
Section 13.10.5 (page 99) of the SAM3U programmer's guide states that unaligned accesses are supported only by the load/store instructions LDRx and STRx. Various system management accesses (exception vectors, for instance), including the thumb-2 instructions must be properly aligned. The LDRx and STRx instructions are the standard memory access instructions and therefore support unaligned access, possibly with a performance impact.
Don't try to use the load multiple, store multiple or exclusive access instructions, or try to run the stack on unaligned boundaries.
Plenty of people on this site have been there, done that and know how much it costs.
Assuming that Murdoch's rag isn't lying about the story (a point that's been made and worth considering), those of us who both do comms security and have worked with profit-oriented military contractors, know all too well that there are too many times when incompetence is the rule not the exception.
I installed a Linux distribution on a friend's laptop a few years ago, and have heard *nothing* from her, other than occasionally that it's working just fine. She uses my wife's office several times a week, which means that she has lots of opportunities to ask for help, or to complain if she sees something not working to her satisfaction.
Yup, it was sortof cute to see all those official-looking Windows-themed widgets showing up on my Linux-hosted Firefox.
It pisses me off but in a somewhat abstract way to see asswipes like that try to take advantage of people.
It would piss me off in a direct and non-abstract way if I ended up with the job of fixing my wife's Windows system if it were infected by some bogus malware. My wife is stuck using a Windows system to support a few necessary programs, and though we have multiple layers of protections I fairly sure she (a psychologist) is not prepared to mitigate these risks independent of my help.
I get so tired of the extra effort it takes to keep her system running. Damnit, we paid *extra* for Microsoftt software, we paid *extra* for many of the programs she depends on. My workstations are so much less labor-intensive and get so much more work done...
We are talking about basic research in general, and my comment was about entrenched interests bleating about "socialism" to preserve their lucrative and influential business models. What they are doing though is discouraging research that would be helpful in preserving national security.
Dude, in case you missed it, petroleum imports are a significant part of our trade imbalance, contributing to the movement of lots of capital offshore. That's not a "slander", it's a whole fucking shitload of our money.
On the use of military power to protect access to energy, again there are lots and lots of real asshole leaders in the world, constantly threatening their neighbors. But the only one the U.S. got all military with, was Iraq. Twice.
In 1952-1953, the U.S. helped Britain overthrow the elected leadership of Iran, mostly because they were getting uppity and nationalizing their oil. This isn't slander, it's a whole pissed-off country because the U.S. and Britain were fucking around with their society. For oil.
This was a slashdot comment. On word usage big guy, I cite definition 3 from a common online dictionary.
Energy research management is being managed with such monumental incompetence that somebody has to step in. Here is a quote from the preamble of the U.S. Constitution (citation):... promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity....
The whole purpose of "the government" is to be instrumental in preserving our national security. Economic security counts too, and this society has been woefully inadequate in preparing for the days when petroleum either gets expensive or becomes a weapon of economic dominance.
Forget the flowery language. It's real goddamned simple: This country has blown a shitload of our capital and our international reputation to preserve access to petroleum resources. It's time to regain control of our own destiny by developing our own energy resources. The research that would have made this a much less painful process could have been done decades ago.
And your response is a perfect example of what I mean when I talk about entrenched interests screaming "socialism" to prevent us from coming to a broad consensus to prepare for conditions that will occur sooner or later.
Slashdot Mirror
Q1. How often have you misplaced your car key? (Be honest now..)
Never.
Q2. How often have you accidently locked a car, whle the keys were in it? (Remember - honest answers, now..)
Never.
QA. How often have you ever forgoten a pasword?
QB. How often (exactly) have you personally lost/had a computer stolen, and still cared more about whether or not the processor sill worked than your data?
Gratefully, I've never had such a thing happen, but the data has always been worth waaay more than the computer.
Add up sum from answers Q1 & Q2, subtract number of times QB is applicable, multiply resulting number by QA & the number of days to Christmas (In the Year 2525), then.. ..boycott this (and every other) backdoor BS, seriously.
I have always locked doors with the key. ("always" == every single time I've locked a door, it was done with the key. I often don't bother to lock my friendly old car.)
I have an IronKey® and did in fact forget the password to it, for the first 7 of 10 tries. Fortunately I finally remembered it and still have use of it.
My wife's psychology business requires us to keep our equipment under lock and key, so we do. I am adding additional crypto layers as we speak, just to make sure. I don't think it's worth trying to prevent NSA-quality spying on my wife's patient appointment records, but your average cracker should have a pretty difficult time with it. Remote disable is far less interesting to me than good security policy.
Joking aside, I will not voluntarily depend on a device that can be easily disabled remotely. Yes, I have an Android® phone, and no I don't depend on it.
From the comments in the WSJ online, people who rode in them described them as nearly silent.
The sequel was, in my opinion, as interesting as the original novel. Jones delved into some uncomfortable social (to me) territory, then finished up with a nice Faustian twist. (Damn, I read the *sequel* 35 years ago.... where DOES the time go?)
Citation required.
So far as I've read and seen on this disaster, not one word has been spoken of or about the oil rig employees, other than ones who got their asses killed because "accidents happen". I have read and seen multiple reports about multiple failures by decisionmakers to cut corners in an enterprise whose risks are significant and (if not precisely known) are legendary. Worse, the costs of failure in this particular enterprise are massive and ongoing dislocation of large numbers of people whose productive lives depend on the gulf of Mexico.
So you have tried to twist an argument about decisionmakers behaving in a criminally negligent way, into personal risk of oil rig employees facing an angry mob.
It is an invalid and in my opinion irresponsible argument.
I've read your comments in other threads and you are both smarter and wiser than this.
... retirement with resources that would serve as comfortable retirement packages for, I'm guessing, 100 middle-class families.
Every time I hear this bullshit about the board serving stockholders and the CEO serving the board, I remember that they tend to downsize from 6 yachts to 4, and from 6 chalets to 2.
And we have politicians running for office in the upcoming U.S. elections demanding that "the government get its boot heel off BP's throat".
This is how we treat those whose decisions lead to catastrophic consequences for society and the people who actually have to work for a living. Drop their $200 million retirement package all the way down to $130 million. Tough shit for those executives.
I am old enough to remember the oil shocks of the 70's and the national response to them. People thought a little bit about efficiency, and for a few years demanded research funding on alternatives. The result was a 25% (or so) drop in demand for "oil" and its derivatives. Those events pissed off the top executives, so they began a comprehensive and sustained war against any credible replacement of their product, or even for ways to dilute their market power.
I have been thinking about what you are saying here for 30 years.
Every single year it's the same damn story: "Don't touch our energy supply! It will destroy the economy!"
Not once have I heard anyone with real influence say something new like "We should really be researching how to manage a transition away from what appears to be a limited, environmentally risky, and internationally de-stabilizing energy supply."
The incumbents (oil execs, etc.) have succeeded in preventing this society from even trying to figure out how to be economically viable if/when it becomes necessary to move beyond petroleum. So now we have people noting (unfortunately correctly) how dependent we are on the decisions of between 60 and 200 boards of directors of the major energy companies.
All that talk about "the market" is totally fucking bogus. The fact is that all of western society is stuck with the planning decisions of those executives. I hear libertarians and conservatives talk about the government all the time talking about "private industry" having the "freedom to innovate".
Sorry guys, those executives and a few others (the top few banking institutions, the top few media companies, etc.) are basically running things exactly the way the planned economies of yore were run, with the same effects: An absolutely perfect record of failure to manage change effectively.
The people directing the energy industry have been careful to prevent significant research into alternatives to their product for *decades*.
I am bloody tired of hearing the strawman argument that says "we cannot move away from oil today, so don't do a goddamned thing about what may be a looming economic problem in the near future!". Nobody is saying "drop all oil all at once immediately". Some people are saying, "Let's get moving on methods, practices and technologies that reduce our dependence on a resource that destabilizes world politics (it's already difficult enough even without the perversions of energy supply management), and which evidently can fuck over entire regions of ocean, shoreline, etc.
The major oil companies have had their lobbying industry working overtime for 40 years to preserve their status as the most important players in an industry that that influences every other major economic activity.
To summarize: It is way past time to begin looking seriously for ways and means for delivering the capabilities that oil has provided historically. And the pussies who are afraid to compete in an truly open marketplace where they don't own a major fraction of our infrastructure can just shut the fuck up, they've had their run and it's time to re-establish a properly competitive marketplace for energy.
As far as I've been able to tell during 40 years of watching and reading, the change that wold be most beneficial to most people in society is the single most important characteristic of alternative sources as they are currently conceived: Decentralization of supply and consequently loss of control over this critical component of our infrastructure.
Under NO CIRCUMSTANCES will the major oil companies allow the growth of technologies that reduce their influence on our energy supply. As long as "oil" and "coal" remain highly capitalized and highly centralized their managers/executives have influence over the choices our society makes due to their control over a large fraction of our energy supply, they are pulling in major profits both as companies and as individual major stock holders.
That is fucking stupid.
The central tenet of net neutrality is, get ready for it....
neutrality
No corporate executive dictation.
You may or may not be old enough to remember the days before internet freedom, when there was a *MAJOR* toll to be paid by anyone wishing to cross the boundaries established by manufacturers (Hello, IBM of the '70's) or providers (hello, AT&T before Carterfone) or postal/telegraph monopolies (hello, old Europe).
Then came along a non-encumbered, free and open internet.
???
Piles and SHITLOADS of profit, growing every day. Providing room for anyone with the willingness and ability to compete openly and freely.
Net neutrality is, by definition, freedom: The free flow of information among those who would exchange it, independent of corporate desire to limit that freedom.
I thought it was reasonably well understood that one of Walmart's primary characteristics is their *amazing* control over logistics. In fact, I thought one of their big process inventions was to bring logistical activity online.
I welcome clarification, since I haven't worked for Walmart.
Been there, done that: Assembly, FORTRAN (II, IV, V), COBOL, PL/1. (I remember when DB2 rented for several grand per month.)
Developing has gotten way more easier, though what I've found is that the expectations are way more greater [sic]. Many experiments have died on the vine, but as you note, we needed those experiments to find the right solutions.
Agreed: My experience supports the hypothesis.
Our development organization is heavily invested in PostgreSQL, finding it to be perfectly matched to almost all of our needs. It is exceptionally reliable, and is very (but not perfectly) manageable. (We've had issues in the past with mis-timed auto-VACUUM for instance which are now resolved.) We even found a small but significant corner-case bug which upon being reported, received immediate attention from the developers, resulting in a resolution in under 72 hours. I believe our use of this particular tool has saved us significant resources (dollars, developer time) that has allowed the development organization to direct our time and money to our own application development.
But we're finding that even PostgreSQL has limits, mostly with respect to the large and growing datasets our application uses for large scale real time control. We could transition to a really expensive SQL solution, but we are at least considering the choices that may be a better fit for these particular subsystems than PostgreSQL or any other SQL solution. Just a few weeks ago, we started seeing a good comment in teh interWebs... "NoSQL" should mean "not only SQL".
Not a rejection of a powerful toolkit that holds a central role in our organization, but rather a recognition that we would be remiss in our responsibilities if we didn't pay attention to the choices that could simplify our lives as developers.
Being happily ensconced in the bare metal world (Cortex-M3: Nice machine), I would be careful about using the word "inferior".One starts to count bytes and k's when the *entire system cost* is under $25.00 including power supplies.
With that being said, most embedded developers do the bulk of their work in C and on occasion C++ (with great care), with very little assembly support. For what it's worth, most CPU developers are aware of the transition to C and have done an excellent job of making it possible to do almost all system management, including exceptions/faults/priority/interrupts, in C with very little ASM. Where ASM does become necessary, it's usually expressed in a function-call form that keeps the C code neat and clean.
Heh. I ran many of my CS projects on the PDP-8L in an Industrial Engineering lab rather than the IBM 370/168 upstairs.
I used a Fortran IV compiler whose compiled output was intended to run directly on add-on floating point hardware. DEC had a floating point emulator for us poor folks so I ran my projects in a virltualized environment on an 8 kword PDP-8L in 1976.
Upstairs the rich guys with computing center accounts (time was so expensive that one needed authorization to use a real computer) could use either CMS or VM/370 interactively, or OS/MVT. I believe the 370 had the add-on dynamic address translation hardware but cannot prove it.
Back then, people were exceptionally territorial with their systems and permission to use them.
... using RSX emulation. I can no longer remember the compiler we used . Maybe Whitesmiths? But I do remember needing to implement a really basic :-) stdio library.
By the time we were finished with the project, we had implemented a client-server data management system (it could not be called a database) that supported transactions, ordered indexes and never lost a record through years of operation.
The company ended up replacing a PDP-11/73 with a SparcServer 2 in 1990, I think.
We're using the downloadable version of the Code Sourcery toolchain, to which we were directed by Atmel. FWIW, (IMHO) Code Sourcery has done a good job of collecting the often disparate components that make up a good toolchain.
I am operating under a basic assumption that converting from an old-school 8-bitter to the CortexM3 is guaranteed to take some careful thinking, planning and verification using various tools (particularly including objdump!)...
> /home/lcs/armdev_2009q3/bin/arm-none-eabi-gcc -v /scratch/julian/2009q3-respin-eabi-lite/src/gcc-4.4/configure --build=i686-pc-linux-gnu --host=i686-pc-linux-gnu --target=arm-none-eabi --enable-threads --disable-libmudflap --disable-libssp --disable-libstdcxx-pch --enable-extra-sgxxlite-multilibs --with-gnu-as --with-gnu-ld --with-specs='%{O2:%{!fno-remove-local-statics: -fremove-local-statics}} %{O*:%{O|O0|O1|O2|Os:;:%{!fno-remove-local-statics: -fremove-local-statics}}}' --enable-languages=c,c++ --disable-shared --disable-lto --with-newlib --with-pkgversion='Sourcery G++ Lite 2009q3-68' --with-bugurl=https://support.codesourcery.com/GNUToolchain/ --disable-nls --prefix=/opt/codesourcery --with-headers=yes --with-sysroot=/opt/codesourcery/arm-none-eabi --with-build-sysroot=/scratch/julian/2009q3-respin-eabi-lite/install/arm-none-eabi --with-gmp=/scratch/julian/2009q3-respin-eabi-lite/obj/host-libs-2009q3-68-arm-none-eabi-i686-pc-linux-gnu/usr --with-mpfr=/scratch/julian/2009q3-respin-eabi-lite/obj/host-libs-2009q3-68-arm-none-eabi-i686-pc-linux-gnu/usr --with-ppl=/scratch/julian/2009q3-respin-eabi-lite/obj/host-libs-2009q3-68-arm-none-eabi-i686-pc-linux-gnu/usr --with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm' --with-cloog=/scratch/julian/2009q3-respin-eabi-lite/obj/host-libs-2009q3-68-arm-none-eabi-i686-pc-linux-gnu/usr --disable-libgomp --enable-poison-system-directories --with-build-time-tools=/scratch/julian/2009q3-respin-eabi-lite/install/arm-none-eabi/bin --with-build-time-tools=/scratch/julian/2009q3-respin-eabi-lite/install/arm-none-eabi/bin
Using built-in specs.
Target: arm-none-eabi
Configured with:
Thread model: single
gcc version 4.4.1 (Sourcery G++ Lite 2009q3-68)
typedef struct {
unsigned char a;
unsigned short b;
unsigned short c;
} pstruct1;
typedef struct { ..... in "main"....
unsigned char a;
unsigned short b;
unsigned short c;
} __attribute__((packed)) pstruct2;
printf("sizeof(pstruct1)=%d, sizeof(pstruct2)=%d\r\n", sizeof(pstruct1), sizeof(pstruct2));
sizeof(pstruct1)=6, sizeof(pstruct2)=5
I'll check back occasionally to see if you have further questions; since I'm in the early stages of this porting process, I have plenty of questions and welcome additional thoughts.
Sorry about the late response, I've been tracking down endianness, packing and crypto issues in the comms layer of this porting job.
Not at work yet and too lazy to set up the VPN connection...
Initial response is that the compiler's default is natural alignment, which needs to be disabled by use of the explicit __attribute__((packed)).
I just finished sweeping our snowy driveway, and am headed into work soon. I'll let you know what I learn.
You refer to "cc" as if this were compiling natively. FWIW, my use case is cross-compilation of thumb-2 code on an X86_64 host.
It's a comfortably snide comment but it does not reflect the decades-long reality of the ARM architecture.
The ARM guys started out in a performance/watt sweet spot from the beginning and they continue to get it right today.
Not to sound disagreeable, I had exactly the attitude you describe. But having been convinced (OK, forced) to develop for a Cortex-M3 (thumb-2 ONLY) part, I've become convinced that the thumb-2 instruction set is actually very good. It offers excellent code density, while still allowing me to code "just the way I want". I have checked several basic routines that we depend on for our work, and as far as I am concerned, the ARM guys have hit the sweet spot for the work we're doing in our embedded project.
I checked a fair amount of bit-twiddling functionality, including CRC-16 (big and little-endian), a few basic crypto functions, and general structure access.
Though not specifically related to thumb-2 "cruft", I believe another significant improvement in the ARM approach is that they have built an excellent stack/exception entry and return model that does a surprisingly good job of reducing our dependence on assembly language escapes or functions. Almost the entire processor, peripheral blocks, system control initialization is done in C with the contribution of a few ASM escapes that are coded to behave as ordinary functions. In the cortex world, ARM refers to this as "CMSIS", the "cortex Microcontroller Software Interface Standard".
I am porting an IEEE 802.15.4 (physical layer compatibility only, proprietary protocol) system from an old school 8/16 bit CPU to a cortex-M3 (Atmel AT91SAM3U4) right now. Having been coded on the byte-wide machine, all sorts of protocol structures have odd alignments.
I have verified that the new CPU is tolerant of unaligned accesses, both of shorts on odd boundaries and longs on both odd byte and odd-halfword boundaries. Forcing GCC to compile the "unnatural" packing requires the use of an attribute:
typedef struct
{
unsigned char uc1;
unsigned int ui1 __attribute__((packed));
unsigned short us1 __attribute__((packed));
} Pstruct;
(I am typing this from memory, it may not be just right but should communicate the basic idea.)
Section 13.10.5 (page 99) of the SAM3U programmer's guide states that unaligned accesses are supported only by the load/store instructions LDRx and STRx. Various system management accesses (exception vectors, for instance), including the thumb-2 instructions must be properly aligned. The LDRx and STRx instructions are the standard memory access instructions and therefore support unaligned access, possibly with a performance impact.
Don't try to use the load multiple, store multiple or exclusive access instructions, or try to run the stack on unaligned boundaries.
Plenty of people on this site have been there, done that and know how much it costs.
Assuming that Murdoch's rag isn't lying about the story (a point that's been made and worth considering), those of us who both do comms security and have worked with profit-oriented military contractors, know all too well that there are too many times when incompetence is the rule not the exception.
I installed a Linux distribution on a friend's laptop a few years ago, and have heard *nothing* from her, other than occasionally that it's working just fine. She uses my wife's office several times a week, which means that she has lots of opportunities to ask for help, or to complain if she sees something not working to her satisfaction.
Yup, it was sortof cute to see all those official-looking Windows-themed widgets showing up on my Linux-hosted Firefox.
It pisses me off but in a somewhat abstract way to see asswipes like that try to take advantage of people.
It would piss me off in a direct and non-abstract way if I ended up with the job of fixing my wife's Windows system if it were infected by some bogus malware. My wife is stuck using a Windows system to support a few necessary programs, and though we have multiple layers of protections I fairly sure she (a psychologist) is not prepared to mitigate these risks independent of my help.
I get so tired of the extra effort it takes to keep her system running. Damnit, we paid *extra* for Microsoftt software, we paid *extra* for many of the programs she depends on. My workstations are so much less labor-intensive and get so much more work done...
We are talking about basic research in general, and my comment was about entrenched interests bleating about "socialism" to preserve their lucrative and influential business models. What they are doing though is discouraging research that would be helpful in preserving national security.
Slander? Talking point?
Dude, in case you missed it, petroleum imports are a significant part of our trade imbalance, contributing to the movement of lots of capital offshore. That's not a "slander", it's a whole fucking shitload of our money.
On the use of military power to protect access to energy, again there are lots and lots of real asshole leaders in the world, constantly threatening their neighbors. But the only one the U.S. got all military with, was Iraq. Twice.
In 1952-1953, the U.S. helped Britain overthrow the elected leadership of Iran, mostly because they were getting uppity and nationalizing their oil. This isn't slander, it's a whole pissed-off country because the U.S. and Britain were fucking around with their society. For oil.
This was a slashdot comment. On word usage big guy, I cite definition 3 from a common online dictionary.
Energy research management is being managed with such monumental incompetence that somebody has to step in. Here is a quote from the preamble of the U.S. Constitution (citation): ... promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity....
The whole purpose of "the government" is to be instrumental in preserving our national security. Economic security counts too, and this society has been woefully inadequate in preparing for the days when petroleum either gets expensive or becomes a weapon of economic dominance.
Forget the flowery language. It's real goddamned simple: This country has blown a shitload of our capital and our international reputation to preserve access to petroleum resources. It's time to regain control of our own destiny by developing our own energy resources. The research that would have made this a much less painful process could have been done decades ago.
And your response is a perfect example of what I mean when I talk about entrenched interests screaming "socialism" to prevent us from coming to a broad consensus to prepare for conditions that will occur sooner or later.