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Diffstat (limited to 'src/isaac.c')
-rw-r--r-- | src/isaac.c | 110 |
1 files changed, 0 insertions, 110 deletions
diff --git a/src/isaac.c b/src/isaac.c deleted file mode 100644 index 014c4d9..0000000 --- a/src/isaac.c +++ /dev/null @@ -1,110 +0,0 @@ -/* ------------------------------------------------------------------------------- -isaac.c: By Bob Jenkins. My random number generator, ISAAC. -MODIFIED: - 960327: Creation (addition of randinit, really) - 970719: use context, not global variables, for internal state - 980324: make a portable version - 991209: modified for inclusion with GNU Backgammon by Gary Wong - 070121: modified for inclusion with flam3 by Erik Reckase ------------------------------------------------------------------------------- -*/ - -#include "isaacs.h" -#include "isaac.h" - -#define ind(mm,x) ((mm)[(x>>2)&(RANDSIZ-1)]) -#define rngstep(mix,a,b,mm,m,m2,r,x) \ -{ \ - x = *m; \ - a = ((a^(mix)) + *(m2++)) & 0xffffffff; \ - *(m++) = y = (ind(mm,x) + a + b) & 0xffffffff; \ - *(r++) = b = (ind(mm,y>>RANDSIZL) + x) & 0xffffffff; \ -} - -void isaac(randctx *ctx) -{ - register ub4 a,b,x,y,*m,*mm,*m2,*r,*mend; - mm=ctx->randmem; r=ctx->randrsl; - a = ctx->randa; b = (ctx->randb + (++ctx->randc)) & 0xffffffff; - for (m = mm, mend = m2 = m+(RANDSIZ/2); m<mend; ) - { - rngstep( a<<13, a, b, mm, m, m2, r, x); - rngstep( a>>6 , a, b, mm, m, m2, r, x); - rngstep( a<<2 , a, b, mm, m, m2, r, x); - rngstep( a>>16, a, b, mm, m, m2, r, x); - } - for (m2 = mm; m2<mend; ) - { - rngstep( a<<13, a, b, mm, m, m2, r, x); - rngstep( a>>6 , a, b, mm, m, m2, r, x); - rngstep( a<<2 , a, b, mm, m, m2, r, x); - rngstep( a>>16, a, b, mm, m, m2, r, x); - } - ctx->randb = b; ctx->randa = a; -} - - -#define mix(a,b,c,d,e,f,g,h) \ -{ \ - a^=b<<11; d+=a; b+=c; \ - b^=c>>2; e+=b; c+=d; \ - c^=d<<8; f+=c; d+=e; \ - d^=e>>16; g+=d; e+=f; \ - e^=f<<10; h+=e; f+=g; \ - f^=g>>4; a+=f; g+=h; \ - g^=h<<8; b+=g; h+=a; \ - h^=a>>9; c+=h; a+=b; \ -} - -/* if (flag==TRUE), then use the contents of randrsl[] to initialize mm[]. */ -void irandinit(randctx *ctx, word flag) -{ - word i; - ub4 a,b,c,d,e,f,g,h; - ub4 *m,*r; - ctx->randa = ctx->randb = ctx->randc = 0; - m=ctx->randmem; - r=ctx->randrsl; - a=b=c=d=e=f=g=h=0x9e3779b9; /* the golden ratio */ - - for (i=0; i<4; ++i) /* scramble it */ - { - mix(a,b,c,d,e,f,g,h); - } - - if (flag) - { - /* initialize using the contents of r[] as the seed */ - for (i=0; i<RANDSIZ; i+=8) - { - a+=r[i ]; b+=r[i+1]; c+=r[i+2]; d+=r[i+3]; - e+=r[i+4]; f+=r[i+5]; g+=r[i+6]; h+=r[i+7]; - mix(a,b,c,d,e,f,g,h); - m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d; - m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h; - } - /* do a second pass to make all of the seed affect all of m */ - for (i=0; i<RANDSIZ; i+=8) - { - a+=m[i ]; b+=m[i+1]; c+=m[i+2]; d+=m[i+3]; - e+=m[i+4]; f+=m[i+5]; g+=m[i+6]; h+=m[i+7]; - mix(a,b,c,d,e,f,g,h); - m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d; - m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h; - } - } - else - { - for (i=0; i<RANDSIZ; i+=8) - { - /* fill in mm[] with messy stuff */ - mix(a,b,c,d,e,f,g,h); - m[i ]=a; m[i+1]=b; m[i+2]=c; m[i+3]=d; - m[i+4]=e; m[i+5]=f; m[i+6]=g; m[i+7]=h; - } - } - - isaac(ctx); /* fill in the first set of results */ - ctx->randcnt=RANDSIZ; /* prepare to use the first set of results */ -} |