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author | Thiago Macieira <thiago.macieira@nokia.com> | 2010-09-02 09:54:11 (GMT) |
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committer | Thiago Macieira <thiago.macieira@nokia.com> | 2010-09-02 10:27:06 (GMT) |
commit | f700d92ad259e3c4ddc6adf04069e200403b028a (patch) | |
tree | eeb62bedd91f330c0e59235d9cb6010c1df97ccd /src | |
parent | 23393f9650624bcc82942ee69161b6b916fa801e (diff) | |
download | Qt-f700d92ad259e3c4ddc6adf04069e200403b028a.zip Qt-f700d92ad259e3c4ddc6adf04069e200403b028a.tar.gz Qt-f700d92ad259e3c4ddc6adf04069e200403b028a.tar.bz2 |
Update the cpuid code to be better
There's no need to test and retest if the cpuid instruction is present
on 32-bit. There's no need to test it at all on 64-bit.
We don't know why, but it also fixes some problems on 64-bit.
Approving-nod-from: Bradley Hughes
Diffstat (limited to 'src')
-rw-r--r-- | src/corelib/tools/qsimd.cpp | 106 |
1 files changed, 37 insertions, 69 deletions
diff --git a/src/corelib/tools/qsimd.cpp b/src/corelib/tools/qsimd.cpp index 68ab033..7349432 100644 --- a/src/corelib/tools/qsimd.cpp +++ b/src/corelib/tools/qsimd.cpp @@ -140,56 +140,41 @@ static inline uint detectProcessorFeatures() uint result = 0; /* see p. 118 of amd64 instruction set manual Vol3 */ #if defined(Q_CC_GNU) - asm ("push %%ebx\n" - "pushf\n" - "pop %%eax\n" - "mov %%eax, %%ebx\n" - "xor $0x00200000, %%eax\n" - "push %%eax\n" - "popf\n" - "pushf\n" - "pop %%eax\n" - "xor %%edx, %%edx\n" - "xor %%ebx, %%eax\n" - "jz 1f\n" - - "mov $0x00000001, %%eax\n" - "cpuid\n" - "1:\n" - "pop %%ebx\n" - "mov %%edx, %0\n" - "mov %%ecx, %1\n" - : "=r" (result), "=r" (feature_result) - : - : "%eax", "%ecx", "%edx" - ); - - asm ("push %%ebx\n" - "pushf\n" - "pop %%eax\n" - "mov %%eax, %%ebx\n" - "xor $0x00200000, %%eax\n" - "push %%eax\n" + long cpuid_supported, tmp1; + asm ("pushf\n" + "pop %0\n" + "mov %0, %1\n" + "xor $0x00200000, %0\n" + "push %0\n" "popf\n" "pushf\n" - "pop %%eax\n" - "xor %%edx, %%edx\n" - "xor %%ebx, %%eax\n" - "jz 2f\n" - - "mov $0x80000000, %%eax\n" - "cpuid\n" - "cmp $0x80000000, %%eax\n" - "jbe 2f\n" - "mov $0x80000001, %%eax\n" - "cpuid\n" - "2:\n" - "pop %%ebx\n" - "mov %%edx, %0\n" - : "=r" (extended_result) - : - : "%eax", "%ecx", "%edx" - ); + "pop %0\n" + "xor %1, %0\n" // %eax is now 0 if CPUID is not supported + : "=a" (cpuid_supported), "=r" (tmp1) + ); + if (cpuid_supported) { + asm ("xchg %%ebx, %2\n" + "cpuid\n" + "xchg %%ebx, %2\n" + : "=c" (feature_result), "=d" (result), "=&r" (tmp1) + : "a" (1)); + + asm ("xchg %%ebx, %1\n" + "cpuid\n" + "cmp $0x80000000, %%eax\n" + "jnbe 1f\n" + "xor %0, %0\n" + "jmp 2f\n" + "1:\n" + "mov $0x80000001, %%eax\n" + "cpuid\n" + "2:\n" + "xchg %%ebx, %1\n" + : "=d" (extended_result), "=&r" (tmp1) + : "a" (0x80000000) + : "%ecx" + ); + } #elif defined (Q_OS_WIN) _asm { @@ -289,27 +274,10 @@ static inline uint detectProcessorFeatures() uint feature_result = 0; #if defined(Q_CC_GNU) - asm ("push %%rbx\n" - "pushf\n" - "pop %%rax\n" - "mov %%eax, %%ebx\n" - "xor $0x00200000, %%eax\n" - "push %%rax\n" - "popf\n" - "pushf\n" - "pop %%rax\n" - "xor %%edx, %%edx\n" - "xor %%ebx, %%eax\n" - "jz 1f\n" - - "mov $0x00000001, %%eax\n" - "cpuid\n" - "1:\n" - "pop %%rbx\n" - "mov %%ecx, %0\n" - : "=r" (feature_result) - : - : "%eax", "%ecx", "%edx" + asm ("cpuid" + : "=c" (feature_result) + : "a" (1) + : "%ebx", "%edx" ); #elif defined (Q_OS_WIN64) { |