Filter
Top Products
Chapter 8 Integer Optimizations 189
Software Optimization Guide for AMD64 Processors
25112 Rev. 3.06 September 2005
printf("; dividend: register other than EAX or memory location\n");
printf("\n");
printf("MOV EAX, 0%08lXh\n", m);
printf("MUL dividend\n");
if (s) printf("SHR EDX, %d\n", s);
printf("\n");
printf("; quotient now in EDX\n");
}
printed_code:
fprintf(stderr, "\n");
exit(0);
return(0);
}
Signed Integer Division
The utility sdiv.exe was compiled using the following code. The utilities provided in this document
are for reference only and are not supported by AMD.
Example Code
/* This program determines the algorithm (a), multiplier (m), and
shift factor (s) to be used to accomplish *signed* division by
a constant divisor. Compile with MSVC.
*/
#include <stdio.h>
typedef unsigned __int64 U64;
typedef unsigned long U32;
U32 log2(U32 i)
{
U32 t = 0;
i = i >> 1;
while (i) {
i = i >> 1;
t++;
}
return(t);
}
long e;
U32 res1, res2;
U32 oa, os, om;
U32 d, l, s, m, a, r, t;
U64 m_low, m_high, j, k;