diff options
Diffstat (limited to 'peak_sse_assist.s')
| -rw-r--r-- | peak_sse_assist.s | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/peak_sse_assist.s b/peak_sse_assist.s new file mode 100644 index 0000000..ea6fce8 --- /dev/null +++ b/peak_sse_assist.s @@ -0,0 +1,49 @@ +# SSE assist routines for peakval +# Copyright 2001 Phil Karn, KA9Q +# May be used under the terms of the GNU Lesser General Public License (LGPL) + + .text + +# Find peak absolute value in signed 16-bit input samples +# int peakval_sse(signed short *in,int cnt); + .global peakval_sse + .type peakval_sse,@function + .align 16 +peakval_sse: + pushl %ebp + movl %esp,%ebp + pushl %esi + pushl %ecx + + movl 8(%ebp),%esi + movl 12(%ebp),%ecx + + pxor %mm7,%mm7 # clear peak + +1: subl $4,%ecx + jl 2f + movq (%esi),%mm0 + movq %mm0,%mm1 + psraw $15,%mm1 # mm1 = 1's if negative, 0's if positive + pxor %mm1,%mm0 # complement negatives + psubw %mm1,%mm0 # add 1 to negatives + pmaxsw %mm0,%mm7 # store peak + + addl $8,%esi + jmp 1b + +2: movq %mm7,%mm0 + psrlq $32,%mm0 + pmaxsw %mm0,%mm7 + movq %mm7,%mm0 + psrlq $16,%mm0 + pmaxsw %mm0,%mm7 # min value in low word of %mm7 + + movd %mm7,%eax + andl $0xffff,%eax + + emms + popl %ecx + popl %esi + popl %ebp + ret |