diff options
Diffstat (limited to 'peak_sse2_assist.s')
| -rw-r--r-- | peak_sse2_assist.s | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/peak_sse2_assist.s b/peak_sse2_assist.s new file mode 100644 index 0000000..1dee3a8 --- /dev/null +++ b/peak_sse2_assist.s @@ -0,0 +1,51 @@ +# SSE2 assist routines for peakval +# Copyright 2001 Phil Karn, KA9Q +# May be used under the terms of the GNU Public License (GPL) + + .text + +# Find peak absolute value in signed 16-bit input samples +# int peakval_sse2(signed short *in,int cnt); + .global peakval_sse2 + .type peakval_sse2,@function + .align 16 +peakval_sse2: + pushl %ebp + movl %esp,%ebp + pushl %esi + pushl %ecx + + movl 8(%ebp),%esi + movl 12(%ebp),%ecx + + pxor %xmm7,%xmm7 # clear peak + +1: subl $8,%ecx + jl 2f + movaps (%esi),%xmm0 + movaps %xmm0,%xmm1 + psraw $15,%xmm1 # xmm1 = 1's if negative, 0's if positive + pxor %xmm1,%xmm0 # complement negatives + psubw %xmm1,%xmm0 # add 1 to negatives + pmaxsw %xmm0,%xmm7 # store peak + + addl $16,%esi + jmp 1b + +2: movaps %xmm7,%xmm0 + psrldq $8,%xmm0 + pmaxsw %xmm0,%xmm7 + movaps %xmm7,%xmm0 + psrlq $32,%xmm0 + pmaxsw %xmm0,%xmm7 + movaps %xmm7,%xmm0 + psrlq $16,%xmm0 + pmaxsw %xmm0,%xmm7 # min value in low word of %xmm7 + + movd %xmm7,%eax + andl $0xffff,%eax + + popl %ecx + popl %esi + popl %ebp + ret |