------- Comment #1 from rguenth at gcc dot gnu dot org 2007-09-25 12:32 -------
1) umul_ppmm(high_prod, low_prod, multipler, multiplicand) multiplies two
UWtype integers MULTIPLER and MULTIPLICAND, and generates a two UWtype
word product in HIGH_PROD and LOW_PROD.
#define umul_ppmm(w1, w0, u, v) \
__asm__ ("mulq %3" \
: "=a" (w0), "=d" (w1) \
: "%0" ((UDItype)(u)), "rm" ((UDItype)(v)))
7) add_ssaaaa(high_sum, low_sum, high_addend_1, low_addend_1,
high_addend_2, low_addend_2) adds two UWtype integers, composed by
HIGH_ADDEND_1 and LOW_ADDEND_1, and HIGH_ADDEND_2 and LOW_ADDEND_2
respectively. The result is placed in HIGH_SUM and LOW_SUM. Overflow
(i.e. carry out) is not stored anywhere, and is lost.
#define add_ssaaaa(sh, sl, ah, al, bh, bl) \
__asm__ ("addq %5,%q1\n\tadcq %3,%q0" \
: "=r" (sh), "=&r" (sl) \
: "0" ((UDItype)(ah)), "rme" ((UDItype)(bh)), \
"%1" ((UDItype)(al)), "rme" ((UDItype)(bl)))
marking %0 early-clobbered fixes the problem.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33552
