| # 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 |
