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49 lines
925 B
49 lines
925 B
# SSE assist routines for peakval |
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# Copyright 2001 Phil Karn, KA9Q |
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# May be used under the terms of the GNU Lesser General Public License (LGPL) |
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.text |
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# Find peak absolute value in signed 16-bit input samples |
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# int peakval_sse(signed short *in,int cnt); |
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.global peakval_sse |
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.type peakval_sse,@function |
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.align 16 |
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peakval_sse: |
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pushl %ebp |
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movl %esp,%ebp |
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pushl %esi |
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pushl %ecx |
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movl 8(%ebp),%esi |
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movl 12(%ebp),%ecx |
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pxor %mm7,%mm7 # clear peak |
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1: subl $4,%ecx |
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jl 2f |
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movq (%esi),%mm0 |
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movq %mm0,%mm1 |
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psraw $15,%mm1 # mm1 = 1's if negative, 0's if positive |
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pxor %mm1,%mm0 # complement negatives |
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psubw %mm1,%mm0 # add 1 to negatives |
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pmaxsw %mm0,%mm7 # store peak |
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addl $8,%esi |
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jmp 1b |
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2: movq %mm7,%mm0 |
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psrlq $32,%mm0 |
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pmaxsw %mm0,%mm7 |
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movq %mm7,%mm0 |
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psrlq $16,%mm0 |
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pmaxsw %mm0,%mm7 # min value in low word of %mm7 |
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movd %mm7,%eax |
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andl $0xffff,%eax |
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emms |
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popl %ecx |
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popl %esi |
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popl %ebp |
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ret
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