1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
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
|
|
