PowerPC GCC floating point instructions
Currently I am developing for a MPC5777 board, with e200z7 cores. Most of the things are going well, but I am stuck with a problem that is really annoying me already.
I am trying to use floating point operations on portions of my code, using the embedded hardware support. My toolchain is GCC 6.3 (powerpc-gcc), for which I am using the following flags:
ASFLAGS_BASE = -g -a32 -mbooke -me500 --fatal-warnings
ARCH_FLAGS = -mpowerpc-gpopt -mfprnd -misel -m32 -mhard-float -mabi=spe -mmfpgpr -mfloat-gprs=single
Please notice the -mfloat-gprs=single flag. That is the one that is giving problems.
When I use -mfloat-gprs=single, I am not able to compile things properly, as some functions are not implemented:
undefined reference to `__extendsfdf2`,
undefined reference to `__adddf3`,
undefined reference to `__divdf3`,
- among others.
Now, if I compile using -mfloat-gprs=double, it goes till the end and generate all my execution files. BUT, using this flag also generates extra functions, not implemented by the e200z7. I can't tell for sure all of them, as the code is getting bigger and it is mostly impossible to track all generated assembly. For instance, at the moment my execution gets stuck when it reaches the efscfd instruction, which is implemented by the e500 core, that has double precision floating point support, but not for the e200, that has single precision support only.
So, any piece of advice here would be amazingly welcome!
Thanks in advance,
gcc powerpc
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
add a comment |
Currently I am developing for a MPC5777 board, with e200z7 cores. Most of the things are going well, but I am stuck with a problem that is really annoying me already.
I am trying to use floating point operations on portions of my code, using the embedded hardware support. My toolchain is GCC 6.3 (powerpc-gcc), for which I am using the following flags:
ASFLAGS_BASE = -g -a32 -mbooke -me500 --fatal-warnings
ARCH_FLAGS = -mpowerpc-gpopt -mfprnd -misel -m32 -mhard-float -mabi=spe -mmfpgpr -mfloat-gprs=single
Please notice the -mfloat-gprs=single flag. That is the one that is giving problems.
When I use -mfloat-gprs=single, I am not able to compile things properly, as some functions are not implemented:
undefined reference to `__extendsfdf2`,
undefined reference to `__adddf3`,
undefined reference to `__divdf3`,
- among others.
Now, if I compile using -mfloat-gprs=double, it goes till the end and generate all my execution files. BUT, using this flag also generates extra functions, not implemented by the e200z7. I can't tell for sure all of them, as the code is getting bigger and it is mostly impossible to track all generated assembly. For instance, at the moment my execution gets stuck when it reaches the efscfd instruction, which is implemented by the e500 core, that has double precision floating point support, but not for the e200, that has single precision support only.
So, any piece of advice here would be amazingly welcome!
Thanks in advance,
gcc powerpc
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
The doc for-mfloat-gprssays "This option is currently only available on the MPC854x."
– Marc Glisse
Nov 21 '18 at 20:52
Hey Marc, indeed it says. still, it works. I have two "architectures": the board I am working on and qemu. QeMU emulates an e500 core and the board has two e200z7 cores. I have to set the flags individually for each one of them, and the -mfloat-gprs affects directly the outcome for both. In my opinion, the comments regarding this flag are legacy, and do not reflect newer GCC versions.
– Felipe GM
Nov 22 '18 at 18:10
You'll probably have to post to the gcc-help mailing list or create an issue on gcc's bugzilla...
– Marc Glisse
Nov 22 '18 at 18:13
add a comment |
Currently I am developing for a MPC5777 board, with e200z7 cores. Most of the things are going well, but I am stuck with a problem that is really annoying me already.
I am trying to use floating point operations on portions of my code, using the embedded hardware support. My toolchain is GCC 6.3 (powerpc-gcc), for which I am using the following flags:
ASFLAGS_BASE = -g -a32 -mbooke -me500 --fatal-warnings
ARCH_FLAGS = -mpowerpc-gpopt -mfprnd -misel -m32 -mhard-float -mabi=spe -mmfpgpr -mfloat-gprs=single
Please notice the -mfloat-gprs=single flag. That is the one that is giving problems.
When I use -mfloat-gprs=single, I am not able to compile things properly, as some functions are not implemented:
undefined reference to `__extendsfdf2`,
undefined reference to `__adddf3`,
undefined reference to `__divdf3`,
- among others.
Now, if I compile using -mfloat-gprs=double, it goes till the end and generate all my execution files. BUT, using this flag also generates extra functions, not implemented by the e200z7. I can't tell for sure all of them, as the code is getting bigger and it is mostly impossible to track all generated assembly. For instance, at the moment my execution gets stuck when it reaches the efscfd instruction, which is implemented by the e500 core, that has double precision floating point support, but not for the e200, that has single precision support only.
So, any piece of advice here would be amazingly welcome!
Thanks in advance,
gcc powerpc
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
Currently I am developing for a MPC5777 board, with e200z7 cores. Most of the things are going well, but I am stuck with a problem that is really annoying me already.
I am trying to use floating point operations on portions of my code, using the embedded hardware support. My toolchain is GCC 6.3 (powerpc-gcc), for which I am using the following flags:
ASFLAGS_BASE = -g -a32 -mbooke -me500 --fatal-warnings
ARCH_FLAGS = -mpowerpc-gpopt -mfprnd -misel -m32 -mhard-float -mabi=spe -mmfpgpr -mfloat-gprs=single
Please notice the -mfloat-gprs=single flag. That is the one that is giving problems.
When I use -mfloat-gprs=single, I am not able to compile things properly, as some functions are not implemented:
undefined reference to `__extendsfdf2`,
undefined reference to `__adddf3`,
undefined reference to `__divdf3`,
- among others.
Now, if I compile using -mfloat-gprs=double, it goes till the end and generate all my execution files. BUT, using this flag also generates extra functions, not implemented by the e200z7. I can't tell for sure all of them, as the code is getting bigger and it is mostly impossible to track all generated assembly. For instance, at the moment my execution gets stuck when it reaches the efscfd instruction, which is implemented by the e500 core, that has double precision floating point support, but not for the e200, that has single precision support only.
So, any piece of advice here would be amazingly welcome!
Thanks in advance,
gcc powerpc
gcc powerpc
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
edited Nov 22 '18 at 9:00
Jeremy Kerr
1,582920
1,582920
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
asked Nov 20 '18 at 22:06
Felipe GMFelipe GM
3415
3415
The doc for-mfloat-gprssays "This option is currently only available on the MPC854x."
– Marc Glisse
Nov 21 '18 at 20:52
Hey Marc, indeed it says. still, it works. I have two "architectures": the board I am working on and qemu. QeMU emulates an e500 core and the board has two e200z7 cores. I have to set the flags individually for each one of them, and the -mfloat-gprs affects directly the outcome for both. In my opinion, the comments regarding this flag are legacy, and do not reflect newer GCC versions.
– Felipe GM
Nov 22 '18 at 18:10
You'll probably have to post to the gcc-help mailing list or create an issue on gcc's bugzilla...
– Marc Glisse
Nov 22 '18 at 18:13
add a comment |
The doc for-mfloat-gprssays "This option is currently only available on the MPC854x."
– Marc Glisse
Nov 21 '18 at 20:52
Hey Marc, indeed it says. still, it works. I have two "architectures": the board I am working on and qemu. QeMU emulates an e500 core and the board has two e200z7 cores. I have to set the flags individually for each one of them, and the -mfloat-gprs affects directly the outcome for both. In my opinion, the comments regarding this flag are legacy, and do not reflect newer GCC versions.
– Felipe GM
Nov 22 '18 at 18:10
You'll probably have to post to the gcc-help mailing list or create an issue on gcc's bugzilla...
– Marc Glisse
Nov 22 '18 at 18:13
The doc for
-mfloat-gprs says "This option is currently only available on the MPC854x."– Marc Glisse
Nov 21 '18 at 20:52
The doc for
-mfloat-gprs says "This option is currently only available on the MPC854x."– Marc Glisse
Nov 21 '18 at 20:52
Hey Marc, indeed it says. still, it works. I have two "architectures": the board I am working on and qemu. QeMU emulates an e500 core and the board has two e200z7 cores. I have to set the flags individually for each one of them, and the -mfloat-gprs affects directly the outcome for both. In my opinion, the comments regarding this flag are legacy, and do not reflect newer GCC versions.
– Felipe GM
Nov 22 '18 at 18:10
Hey Marc, indeed it says. still, it works. I have two "architectures": the board I am working on and qemu. QeMU emulates an e500 core and the board has two e200z7 cores. I have to set the flags individually for each one of them, and the -mfloat-gprs affects directly the outcome for both. In my opinion, the comments regarding this flag are legacy, and do not reflect newer GCC versions.
– Felipe GM
Nov 22 '18 at 18:10
You'll probably have to post to the gcc-help mailing list or create an issue on gcc's bugzilla...
– Marc Glisse
Nov 22 '18 at 18:13
You'll probably have to post to the gcc-help mailing list or create an issue on gcc's bugzilla...
– Marc Glisse
Nov 22 '18 at 18:13
add a comment |
1 Answer
1
active
oldest
votes
In case someone ends up here with a similar problem, I have fixed it by using three flags:
-mfloat-gprs=single -Wdouble-promotion -fsingle-precision-constant
What they do is:
-mfloat-gprs=single tells the compiler to use general purpose register for floating point operations, instead of floating point registers. =single means it has single precision
-Wdouble-promotion enables a compiler warning for when gcc tries to convert a single float to a double float
-fsingle-precision-constant enforces GCC not to convert single float to double float
I am using -fsingle-precision-constant and -Wdouble-promotion at the same time to be 100% that double will not be used.
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
add a comment |
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1 Answer
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1 Answer
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active
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oldest
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votes
In case someone ends up here with a similar problem, I have fixed it by using three flags:
-mfloat-gprs=single -Wdouble-promotion -fsingle-precision-constant
What they do is:
-mfloat-gprs=single tells the compiler to use general purpose register for floating point operations, instead of floating point registers. =single means it has single precision
-Wdouble-promotion enables a compiler warning for when gcc tries to convert a single float to a double float
-fsingle-precision-constant enforces GCC not to convert single float to double float
I am using -fsingle-precision-constant and -Wdouble-promotion at the same time to be 100% that double will not be used.
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
add a comment |
In case someone ends up here with a similar problem, I have fixed it by using three flags:
-mfloat-gprs=single -Wdouble-promotion -fsingle-precision-constant
What they do is:
-mfloat-gprs=single tells the compiler to use general purpose register for floating point operations, instead of floating point registers. =single means it has single precision
-Wdouble-promotion enables a compiler warning for when gcc tries to convert a single float to a double float
-fsingle-precision-constant enforces GCC not to convert single float to double float
I am using -fsingle-precision-constant and -Wdouble-promotion at the same time to be 100% that double will not be used.
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
add a comment |
In case someone ends up here with a similar problem, I have fixed it by using three flags:
-mfloat-gprs=single -Wdouble-promotion -fsingle-precision-constant
What they do is:
-mfloat-gprs=single tells the compiler to use general purpose register for floating point operations, instead of floating point registers. =single means it has single precision
-Wdouble-promotion enables a compiler warning for when gcc tries to convert a single float to a double float
-fsingle-precision-constant enforces GCC not to convert single float to double float
I am using -fsingle-precision-constant and -Wdouble-promotion at the same time to be 100% that double will not be used.
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
In case someone ends up here with a similar problem, I have fixed it by using three flags:
-mfloat-gprs=single -Wdouble-promotion -fsingle-precision-constant
What they do is:
-mfloat-gprs=single tells the compiler to use general purpose register for floating point operations, instead of floating point registers. =single means it has single precision
-Wdouble-promotion enables a compiler warning for when gcc tries to convert a single float to a double float
-fsingle-precision-constant enforces GCC not to convert single float to double float
I am using -fsingle-precision-constant and -Wdouble-promotion at the same time to be 100% that double will not be used.
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
answered Nov 28 '18 at 20:48
Felipe GMFelipe GM
3415
3415
add a comment |
add a comment |
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The doc for
-mfloat-gprssays "This option is currently only available on the MPC854x."– Marc Glisse
Nov 21 '18 at 20:52
Hey Marc, indeed it says. still, it works. I have two "architectures": the board I am working on and qemu. QeMU emulates an e500 core and the board has two e200z7 cores. I have to set the flags individually for each one of them, and the -mfloat-gprs affects directly the outcome for both. In my opinion, the comments regarding this flag are legacy, and do not reflect newer GCC versions.
– Felipe GM
Nov 22 '18 at 18:10
You'll probably have to post to the gcc-help mailing list or create an issue on gcc's bugzilla...
– Marc Glisse
Nov 22 '18 at 18:13