Linus Torvalds <torvalds@transmeta.com> wrote:
>
>
> On Tue, 11 Mar 2003, Andrew Morton wrote:
> >
> > gcc will generate 64bit * 64bit multiplies without resorting to
> > any library code
>
> However, gcc is unable to do-the-right-thing and generate 32x32->64
> multiplies, or 32x64->64 multiplies, even though those are both a _lot_
> faster than the full 64x64->64 case.
2.95.3 and 3.2.1 seem to do it right?
long a;
long b;
long long c;
void foo(void)
{
c = a * b;
}
.file "t.c"
.version "01.01"
gcc2_compiled.:
.text
.align 4
.globl foo
.type foo,@function
foo:
pushl %ebp
movl %esp,%ebp
movl a,%eax
imull b,%eax
movl %eax,c
cltd
movl %edx,c+4
.L2:
movl %ebp,%esp
popl %ebp
ret
.Lfe1:
.size foo,.Lfe1-foo
.comm a,4,4
.comm b,4,4
.comm c,8,4
.ident "GCC: (GNU) 2.95.3 20010315 (release)"
-
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This archive was generated by hypermail 2b29 : Sat Mar 15 2003 - 22:00:28 EST