[Mesa-stable] [PATCH] mesa: Use SSE prefetch instructions rather than 3DNow instructions
Patrick Baggett
baggett.patrick at gmail.com
Fri Feb 5 20:23:09 CET 2016
On Fri, Feb 5, 2016 at 1:15 PM, Ian Romanick <idr at freedesktop.org> wrote:
> On 02/03/2016 01:54 PM, Timothy Arceri wrote:
>> From: Patrick Baggett <baggett.patrick at gmail.com>
>>
>> 64-bit Pentium 4 CPUs don't have the 3DNow prefetch instructions
>> which results in an Illegal instruction crash.
>
> I'll go out on a limb and say that Pentium4 CPUs never hit the functions
> with 3dnow in the name. I'll go even farther out on the limb and say
> that all CPUs that do hit that path have the... uh... 3DNow prefetch
> instructions.
Ian,
Just to provide some context, the SSE code paths here used PREFETCHW,
which is a 3DNow instruction; this was the source of the crash. I
would additionally guess (though I haven't verified) that the
*_3dnow_* functions are never hit in x86-64 mode because usually code
prefers SSE over 3DNow, and all x86-64 CPUs have SSE2.
Patrick
>
>> Reviewed-by: Roland Scheidegger <sroland at vmware.com>
>> Tested-by: Timothy Arceri <t_arceri at yahoo.com.au>
>> https://bugs.freedesktop.org/show_bug.cgi?id=27512
>> ---
>> src/mesa/x86-64/xform4.S | 40 ++++++++++++++++++++--------------------
>> 1 file changed, 20 insertions(+), 20 deletions(-)
>>
>> diff --git a/src/mesa/x86-64/xform4.S b/src/mesa/x86-64/xform4.S
>> index c185f62..b0aca19 100644
>> --- a/src/mesa/x86-64/xform4.S
>> +++ b/src/mesa/x86-64/xform4.S
>> @@ -69,7 +69,7 @@ _mesa_x86_64_transform_points4_general:
>> movq V4F_START(%rdx), %rdx /* ptr to first src vertex */
>> movq V4F_START(%rdi), %rdi /* ptr to first dest vertex */
>>
>> - prefetch 16(%rdx)
>> + prefetcht1 16(%rdx)
>>
>> movaps 0(%rsi), %xmm4 /* m3 | m2 | m1 | m0 */
>> movaps 16(%rsi), %xmm5 /* m7 | m6 | m5 | m4 */
>> @@ -80,7 +80,7 @@ _mesa_x86_64_transform_points4_general:
>> p4_general_loop:
>>
>> movups (%rdx), %xmm8 /* ox | oy | oz | ow */
>> - prefetchw 16(%rdi)
>> + prefetcht1 16(%rdi)
>>
>> pshufd $0x00, %xmm8, %xmm0 /* ox | ox | ox | ox */
>> addq %rax, %rdx
>> @@ -93,7 +93,7 @@ p4_general_loop:
>> addps %xmm1, %xmm0 /* ox*m3+oy*m7 | ... */
>> mulps %xmm7, %xmm3 /* ow*m15 | ow*m14 | ow*m13 | ow*m12 */
>> addps %xmm2, %xmm0 /* ox*m3+oy*m7+oz*m11 | ... */
>> - prefetch 16(%rdx)
>> + prefetcht1 16(%rdx)
>> addps %xmm3, %xmm0 /* ox*m3+oy*m7+oz*m11+ow*m15 | ... */
>>
>> movaps %xmm0, (%rdi) /* ->D(3) | ->D(2) | ->D(1) | ->D(0) */
>> @@ -150,7 +150,7 @@ _mesa_x86_64_transform_points4_3d:
>> movq V4F_START(%rdx), %rdx /* ptr to first src vertex */
>> movq V4F_START(%rdi), %rdi /* ptr to first dest vertex */
>>
>> - prefetch 16(%rdx)
>> + prefetcht1 16(%rdx)
>>
>> movaps 0(%rsi), %xmm4 /* m3 | m2 | m1 | m0 */
>> movaps 16(%rsi), %xmm5 /* m7 | m6 | m5 | m4 */
>> @@ -166,7 +166,7 @@ _mesa_x86_64_transform_points4_3d:
>> p4_3d_loop:
>>
>> movups (%rdx), %xmm8 /* ox | oy | oz | ow */
>> - prefetchw 16(%rdi)
>> + prefetcht1 16(%rdi)
>>
>> pshufd $0x00, %xmm8, %xmm0 /* ox | ox | ox | ox */
>> addq %rax, %rdx
>> @@ -179,7 +179,7 @@ p4_3d_loop:
>> addps %xmm1, %xmm0 /* ox*m3+oy*m7 | ... */
>> mulps %xmm7, %xmm3 /* ow*m15 | ow*m14 | ow*m13 | ow*m12 */
>> addps %xmm2, %xmm0 /* ox*m3+oy*m7+oz*m11 | ... */
>> - prefetch 16(%rdx)
>> + prefetcht1 16(%rdx)
>> addps %xmm3, %xmm0 /* ox*m3+oy*m7+oz*m11+ow*m15 | ... */
>>
>> movaps %xmm0, (%rdi) /* ->D(3) | ->D(2) | ->D(1) | ->D(0) */
>> @@ -210,8 +210,8 @@ _mesa_x86_64_transform_points4_identity:
>>
>> movq V4F_START(%rdx), %rsi /* ptr to first src vertex */
>> movq V4F_START(%rdi), %rdi /* ptr to first dest vertex */
>> - prefetch 64(%rsi)
>> - prefetchw 64(%rdi)
>> + prefetcht1 64(%rsi)
>> + prefetcht1 64(%rdi)
>>
>> add %ecx, %ecx
>>
>> @@ -242,7 +242,7 @@ _mesa_3dnow_transform_points4_3d_no_rot:
>> movq V4F_START(%rdx), %rdx /* ptr to first src vertex */
>> movq V4F_START(%rdi), %rdi /* ptr to first dest vertex */
>>
>> - prefetch (%rdx)
>> + prefetcht1 (%rdx)
>>
>> movd (%rsi), %mm0 /* | m00 */
>> .byte 0x66, 0x66, 0x90 /* manual align += 3 */
>> @@ -255,7 +255,7 @@ _mesa_3dnow_transform_points4_3d_no_rot:
>>
>> p4_3d_no_rot_loop:
>>
>> - prefetchw 32(%rdi)
>> + prefetcht1 32(%rdi)
>>
>> movq (%rdx), %mm4 /* x1 | x0 */
>> movq 8(%rdx), %mm5 /* x3 | x2 */
>> @@ -279,7 +279,7 @@ p4_3d_no_rot_loop:
>> addq $16, %rdi
>>
>> decl %ecx
>> - prefetch 32(%rdx)
>> + prefetcht1 32(%rdx)
>> jnz p4_3d_no_rot_loop
>>
>> p4_3d_no_rot_done:
>> @@ -311,7 +311,7 @@ _mesa_3dnow_transform_points4_perspective:
>> punpckldq 20(%rsi), %mm0 /* m11 | m00 */
>>
>> movq 32(%rsi), %mm2 /* m21 | m20 */
>> - prefetch (%rdx)
>> + prefetcht1 (%rdx)
>>
>> movd 40(%rsi), %mm1 /* | m22 */
>>
>> @@ -321,7 +321,7 @@ _mesa_3dnow_transform_points4_perspective:
>>
>> p4_perspective_loop:
>>
>> - prefetchw 32(%rdi) /* prefetch 2 vertices ahead */
>> + prefetcht1 32(%rdi) /* prefetch 2 vertices ahead */
>>
>> movq (%rdx), %mm4 /* x1 | x0 */
>> movq 8(%rdx), %mm5 /* x3 | x2 */
>> @@ -347,7 +347,7 @@ p4_perspective_loop:
>> addq $16, %rdi
>>
>> decl %ecx
>> - prefetch 32(%rdx) /* hopefully stride is zero */
>> + prefetcht1 32(%rdx) /* hopefully stride is zero */
>> jnz p4_perspective_loop
>>
>> p4_perspective_done:
>> @@ -374,14 +374,14 @@ _mesa_3dnow_transform_points4_2d_no_rot:
>> movq V4F_START(%rdi), %rdi /* ptr to first dest vertex */
>>
>> movd (%rsi), %mm0 /* | m00 */
>> - prefetch (%rdx)
>> + prefetcht1 (%rdx)
>> punpckldq 20(%rsi), %mm0 /* m11 | m00 */
>>
>> movq 48(%rsi), %mm1 /* m31 | m30 */
>>
>> p4_2d_no_rot_loop:
>>
>> - prefetchw 32(%rdi) /* prefetch 2 vertices ahead */
>> + prefetcht1 32(%rdi) /* prefetch 2 vertices ahead */
>>
>> movq (%rdx), %mm4 /* x1 | x0 */
>> movq 8(%rdx), %mm5 /* x3 | x2 */
>> @@ -394,7 +394,7 @@ p4_2d_no_rot_loop:
>> addq %rax, %rdx
>> pfmul %mm1, %mm6 /* x3*m31 | x3*m30 */
>>
>> - prefetch 32(%rdx) /* hopefully stride is zero */
>> + prefetcht1 32(%rdx) /* hopefully stride is zero */
>> pfadd %mm4, %mm6 /* x1*m11+x3*m31 | x0*m00+x3*m30 */
>>
>> movq %mm6, (%rdi) /* write r0, r1 */
>> @@ -433,7 +433,7 @@ _mesa_3dnow_transform_points4_2d:
>> movd (%rsi), %mm0 /* | m00 */
>> movd 4(%rsi), %mm1 /* | m01 */
>>
>> - prefetch (%rdx)
>> + prefetcht1 (%rdx)
>>
>> punpckldq 16(%rsi), %mm0 /* m10 | m00 */
>> .byte 0x66, 0x66, 0x90 /* manual align += 4 */
>> @@ -443,7 +443,7 @@ _mesa_3dnow_transform_points4_2d:
>>
>> p4_2d_loop:
>>
>> - prefetchw 32(%rdi) /* prefetch 2 vertices ahead */
>> + prefetcht1 32(%rdi) /* prefetch 2 vertices ahead */
>>
>> movq (%rdx), %mm3 /* x1 | x0 */
>> movq 8(%rdx), %mm5 /* x3 | x2 */
>> @@ -460,7 +460,7 @@ p4_2d_loop:
>> pfacc %mm4, %mm3 /* x0*m01+x1*m11 | x0*m00+x1*m10 */
>>
>> pfmul %mm2, %mm6 /* x3*m31 | x3*m30 */
>> - prefetch 32(%rdx) /* hopefully stride is zero */
>> + prefetcht1 32(%rdx) /* hopefully stride is zero */
>>
>> pfadd %mm6, %mm3 /* r1 | r0 */
>>
>>
>
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