On May 17, 2018 2:30:01 PM PDT, Alexey Dobriyan <adobri...@gmail.com> wrote: >32-bit instructions are 1 byte shorter than 16-bit instructions. > >Signed-off-by: Alexey Dobriyan <adobri...@gmail.com> >--- > > arch/x86/kernel/verify_cpu.S | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > >--- a/arch/x86/kernel/verify_cpu.S >+++ b/arch/x86/kernel/verify_cpu.S >@@ -56,14 +56,14 @@ ENTRY(verify_cpu) > cmpl $0x1,%eax > jb .Lverify_cpu_no_longmode # no cpuid 1 > >- xor %di,%di >+ xor %edi, %edi > cmpl $0x68747541,%ebx # AuthenticAMD > jnz .Lverify_cpu_noamd > cmpl $0x69746e65,%edx > jnz .Lverify_cpu_noamd > cmpl $0x444d4163,%ecx > jnz .Lverify_cpu_noamd >- mov $1,%di # cpu is from AMD >+ mov $1, %edi # cpu is from AMD > jmp .Lverify_cpu_check > > .Lverify_cpu_noamd: >@@ -122,13 +122,13 @@ ENTRY(verify_cpu) > andl $SSE_MASK,%edx > cmpl $SSE_MASK,%edx > je .Lverify_cpu_sse_ok >- test %di,%di >+ test %edi, %edi > jz .Lverify_cpu_no_longmode # only try to force SSE on AMD > movl $MSR_K7_HWCR,%ecx > rdmsr > btr $15,%eax # enable SSE > wrmsr >- xor %di,%di # don't loop >+ xor %edi, %edi # don't loop > jmp .Lverify_cpu_sse_test # try again > > .Lverify_cpu_no_longmode:
Well, in 32/64-bit mode... this code is also assembled in 16-bit mode, and the 16-but code is more space sensitive. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
