ocaml/otherlibs/num/bng_ppc.c

95 lines
5.4 KiB
C

/***********************************************************************/
/* */
/* OCaml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 2003 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License, with */
/* the special exception on linking described in file ../../LICENSE. */
/* */
/***********************************************************************/
/* $Id$ */
/* Code specific to the PowerPC architecture. */
#define BngAdd2(res,carryout,arg1,arg2) \
asm("addc %0, %2, %3 \n\t" \
"li %1, 0 \n\t" \
"addze %1, %1" \
: "=r" (res), "=r" (carryout) \
: "r" (arg1), "r" (arg2))
#define BngAdd2Carry(res,carryout,arg1,arg2,carryin) \
asm("addic %1, %4, -1 \n\t" \
"adde %0, %2, %3 \n\t" \
"li %1, 0 \n\t" \
"addze %1, %1" \
: "=r" (res), "=&r" (carryout) \
: "r" (arg1), "r" (arg2), "1" (carryin))
#define BngAdd3(res,carryaccu,arg1,arg2,arg3) \
asm("addc %0, %2, %3 \n\t" \
"addze %1, %1 \n\t" \
"addc %0, %0, %4 \n\t" \
"addze %1, %1" \
: "=&r" (res), "=&r" (carryaccu) \
: "r" (arg1), "r" (arg2), "r" (arg3), "1" (carryaccu))
/* The "subtract" instructions interpret carry differently than what we
need: the processor carry bit CA is 1 if no carry occured,
0 if a carry occured. In other terms, CA = !carry.
Thus, subfe rd,ra,rb computes rd = ra - rb - !CA
subfe rd,rd,rd sets rd = - !CA
subfe rd,rd,rd; neg rd, rd sets rd = !CA and recovers "our" carry. */
#define BngSub2(res,carryout,arg1,arg2) \
asm("subfc %0, %3, %2 \n\t" \
"subfe %1, %1, %1\n\t" \
"neg %1, %1" \
: "=r" (res), "=r" (carryout) \
: "r" (arg1), "r" (arg2))
#define BngSub2Carry(res,carryout,arg1,arg2,carryin) \
asm("subfic %1, %4, 0 \n\t" \
"subfe %0, %3, %2 \n\t" \
"subfe %1, %1, %1 \n\t" \
"neg %1, %1" \
: "=r" (res), "=&r" (carryout) \
: "r" (arg1), "r" (arg2), "1" (carryin))
/* Here is what happens with carryaccu:
neg %1, %1 carryaccu = -carryaccu
addze %1, %1 carryaccu += !carry1
addze %1, %1 carryaccu += !carry2
subifc %1, %1, 2 carryaccu = 2 - carryaccu
Thus, carryaccu_final = carryaccu_initial + 2 - (1 - carry1) - (1 - carry2)
= carryaccu_initial + carry1 + carry2
*/
#define BngSub3(res,carryaccu,arg1,arg2,arg3) \
asm("neg %1, %1 \n\t" \
"subfc %0, %3, %2 \n\t" \
"addze %1, %1 \n\t" \
"subfc %0, %4, %0 \n\t" \
"addze %1, %1 \n\t" \
"subfic %1, %1, 2 \n\t" \
: "=&r" (res), "=&r" (carryaccu) \
: "r" (arg1), "r" (arg2), "r" (arg3), "1" (carryaccu))
#if defined(__ppc64__) || defined(__PPC64__)
#define BngMult(resh,resl,arg1,arg2) \
asm("mulld %0, %2, %3 \n\t" \
"mulhdu %1, %2, %3" \
: "=&r" (resl), "=r" (resh) \
: "r" (arg1), "r" (arg2))
#else
#define BngMult(resh,resl,arg1,arg2) \
asm("mullw %0, %2, %3 \n\t" \
"mulhwu %1, %2, %3" \
: "=&r" (resl), "=r" (resh) \
: "r" (arg1), "r" (arg2))
#endif