+ "JSIMD_ARM_NEON" = "JSIMD_NEON"
+ "JSIMD_MIPS_DSPR2" = "JSIMD_DSPR2"
+ "*_mips_dspr2" = "*_dspr2"
It's obvious that "NEON" refers to Arm and "DSPr2" refers to MIPS, and
this naming convention is consistent with the other SIMD extensions.
Newer versions of CMake (known to be the case with 3.7.x and 3.10.x)
fail to add a space between CMAKE_C_FLAGS and CMAKE_ASM_FLAGS, which
causes the build to fail when using the official build procedure.
Closes#216
Referring to https://docs.microsoft.com/en-US/cpp/build/stack-usage:
"All memory beyond the current address of RSP is considered volatile:
The OS, or a debugger, may overwrite this memory during a user debug
session, or an interrupt handler. Thus, RSP must always be set before
attempting to read or write values to a stack frame."
Basically, if-- under extremely rare circumstances-- a context swap were
to occur between saving the values of xmm8-xmm11 and setting the new
value of rsp, the O/S might not preserve that area of the stack. In
general, libjpeg-turbo should not be using xmm8-xmm11 before or after
the call to jsimd_huff_encode_one_block_sse2(), so this is probably a
non-issue, but it's still a good idea to fix it.
Based on
ff7d2030dd
YASM requires a debug format to be specified with -g. Currently the
only combination that I can make work at all is DWARF-2/ELF (YASM
doesn't support Mach-O debugging at all, and its support for CV8/MSVC
and MinGW/DWARF-2 appears to be broken), so debugging is only enabled
automatically for ELF at the moment. For other formats, we don't
specify -g at all, which is how the old build system behaved.
Fixes#125, Closes#126
+ advertise that full AltiVec SIMD acceleration is now available on
OpenBSD.
The relevant compilers probably all support C99 or GNU's variation of
C90 that allows variables to be declared anywhere, but our policy is to
conform to the C90 standard, if for no other reason than that it
improves code readability.
- Replace CMAKE_SOURCE_DIR with CMAKE_CURRENT_SOURCE_DIR
- Replace CMAKE_BINARY_DIR with CMAKE_CURRENT_BINARY_DIR
- Don't use "libjpeg-turbo" in any of the package system filenames
(because CMAKE_PROJECT_NAME will not be the same if building LJT as
a submodule.)
Closes#122
The previous hack (adding ${CMAKE_ASM_COMPILER} to CMAKE_ASM_FLAGS)
didn't work in all cases, because more recent versions of CMake place
the includes ahead of the flags (which meant that the real assembler
wasn't the first argument to gas-preprocessor.pl.)
Previously, simd/CMakeLists.txt was hard-coded to use NASM, and it was
necessary to override the NASM variable in order to use YASM. This
commit changes the behavior such that NASM is still preferred, but YASM
will be used if it is in the PATH and NASM isn't available. This brings
the actual behavior in line with the behavior described in BUILDING.md.
Based on
b0799a1598Closes#107
Based on
98a5a9dc89
with wordsmithing by DRC.
In the AArch64 ABI, as in many others, it's forbidden to read/store data
below the stack pointer. Some SIMD functions were doing just that
(stack pointer misuse) when trying to preserve callee-saved registers,
and this resulted in those registers being restored with incorrect
contents under certain circumstances.
This patch fixes that behavior, and callee-saved registers are now
stored above the stack pointer throughout the function call. The patch
also removes register saving in places where it is unnecessary for this
ABI, or it makes use of unused scratch regiters instead of callee-saved
registers.
Fixes#97. Closes#101.
Refer also to https://bugzilla.redhat.com/show_bug.cgi?id=1368569
cpuid tells us whether the O/S uses extended state management via
XSAVE/XRSTOR, but we have to call xgetbv to verify that it is using
XSAVE/XRSTOR to manage the state of XMM/YMM registers.
In the AArch64 ABI, the high (unused) DWORD of a 32-bit argument's
register is undefined, so it was incorrect to use 64-bit
instructions to transfer a JDIMENSION argument in the 64-bit NEON SIMD
functions. The code worked thus far only because the existing compiler
optimizers weren't smart enough to do anything else with the register in
question, so the upper 32 bits happened to be all zeroes.
The latest builds of Clang/LLVM have a smarter optimizer, and under
certain circumstances, it will attempt to load-combine adjacent 32-bit
integers from one of the libjpeg structures into a single 64-bit integer
and pass that 64-bit integer as a 32-bit argument to one of the SIMD
functions (which is allowed by the ABI, since the upper 32 bits of the
32-bit argument's register are undefined.) This caused the
libjpeg-turbo regression tests to crash.
This patch tries to use the Wn registers whenever possible. Otherwise,
it uses a zero-extend instruction to avoid using the upper 32 bits of
the 64-bit registers, which are not guaranteed to be valid for 32-bit
arguments.
Based on 1fbae13021Closes#91. Refer also to android-ndk/ndk#110 and
https://llvm.org/bugs/show_bug.cgi?id=28393
This fixes crashes that would occur when attempting to use
libjpeg-turbo's AVX2 extensions on older O/S's (such as Windows XP or
RHEL 5.) Even if the CPU supports AVX2, the O/S has to also support
saving/restoring YMM registers when switching contexts.
