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v0.5.1
https://github.com/python/cpython
09 December 2020, 11:06:31 UTC
Revision 0973b99e1cfe13b3d197e1b6c449a2d75b55d17a authored by Tim Peters on 29 August 2004, 22:16:50 UTC, committed by Tim Peters on 29 August 2004, 22:16:50 UTC 
SF patch 936813: fast modular exponentiation
 
This checkin is adapted from part 1 (of 3) of Trevor Perrin's patch set.

x_mul()
  - sped a little by optimizing the C
  - sped a lot (~2X) if it's doing a square; note that long_pow() squares
    often
k_mul()
  - more cache-friendly now if it's doing a square
KARATSUBA_CUTOFF
  - boosted; gradeschool mult is quicker now, and it may have been too low
    for many platforms anyway
KARATSUBA_SQUARE_CUTOFF
  - new
  - since x_mul is a lot faster at squaring now, the point at which
    Karatsuba pays for squaring is much higher than for general mult
1 parent afb5f94
Raw File
Tip revision: 0973b99e1cfe13b3d197e1b6c449a2d75b55d17a authored by Tim Peters on 29 August 2004, 22:16:50 UTC
SF patch 936813: fast modular exponentiation
Tip revision: 0973b99
memmove.c 

/* A perhaps slow but I hope correct implementation of memmove */

extern char *memcpy(char *, char *, int);

char *
memmove(char *dst, char *src, int n)
{
	char *realdst = dst;
	if (n <= 0)
		return dst;
	if (src >= dst+n || dst >= src+n)
		return memcpy(dst, src, n);
	if (src > dst) {
		while (--n >= 0)
			*dst++ = *src++;
	}
	else if (src < dst) {
		src += n;
		dst += n;
		while (--n >= 0)
			*--dst = *--src;
	}
	return realdst;
}
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