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Use fabs[f]() instead of bit fiddling for setting absolute values.
This makes little difference in float precision, but in double precision gives a speedup of about 30% on amd64 (A64 CPU) and i386 (A64). This depends on fabs[f]() being inline and efficient. The bit fiddling (or any use of SET_HIGH_WORD(), which libm does too much because it was best on old 32-bit machines) always causes packing overheads and sometimes causes stalls in the packing, since it operates on only part of a variable in the double precision case. It apparently did cause stalls in a critical path here.
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svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=177751
@ -60,8 +60,8 @@ __ieee754_hypot(double x, double y)
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GET_HIGH_WORD(hb,y);
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hb &= 0x7fffffff;
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if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
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SET_HIGH_WORD(a,ha); /* a <- |a| */
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SET_HIGH_WORD(b,hb); /* b <- |b| */
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a = fabs(a);
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b = fabs(b);
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if((ha-hb)>0x3c00000) {return a+b;} /* x/y > 2**60 */
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k=0;
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if(ha > 0x5f300000) { /* a>2**500 */
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@ -30,8 +30,8 @@ __ieee754_hypotf(float x, float y)
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GET_FLOAT_WORD(hb,y);
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hb &= 0x7fffffff;
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if(hb > ha) {a=y;b=x;j=ha; ha=hb;hb=j;} else {a=x;b=y;}
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SET_FLOAT_WORD(a,ha); /* a <- |a| */
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SET_FLOAT_WORD(b,hb); /* b <- |b| */
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a = fabsf(a);
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b = fabsf(b);
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if((ha-hb)>0xf000000) {return a+b;} /* x/y > 2**30 */
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k=0;
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if(ha > 0x58800000) { /* a>2**50 */
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