1 # SSE assist routines for peakval 2 # Copyright 2001 Phil Karn, KA9Q 3 # May be used under the terms of the GNU Lesser General Public License (LGPL) 4 5 .text 6 7 # Find peak absolute value in signed 16-bit input samples 8 # int peakval_sse(signed short *in,int cnt); 9 .global peakval_sse 10 .type peakval_sse,@function 11 .align 16 12 peakval_sse: 13 pushl %ebp 14 movl %esp,%ebp 15 pushl %esi 16 pushl %ecx 17 18 movl 8(%ebp),%esi 19 movl 12(%ebp),%ecx 20 21 pxor %mm7,%mm7 # clear peak 22 23 1: subl $4,%ecx 24 jl 2f 25 movq (%esi),%mm0 26 movq %mm0,%mm1 27 psraw $15,%mm1 # mm1 = 1's if negative, 0's if positive 28 pxor %mm1,%mm0 # complement negatives 29 psubw %mm1,%mm0 # add 1 to negatives 30 pmaxsw %mm0,%mm7 # store peak 31 32 addl $8,%esi 33 jmp 1b 34 35 2: movq %mm7,%mm0 36 psrlq $32,%mm0 37 pmaxsw %mm0,%mm7 38 movq %mm7,%mm0 39 psrlq $16,%mm0 40 pmaxsw %mm0,%mm7 # min value in low word of %mm7 41 42 movd %mm7,%eax 43 andl $0xffff,%eax 44 45 emms 46 popl %ecx 47 popl %esi 48 popl %ebp 49 ret 50
