* sysdeps/alpha/divq.S: Save t3 before it gets clobbered.

* sysdeps/alpha/remq.S: Likewise.
        * sysdeps/alpha/div.S, sysdeps/alpha/ldiv.S: Rewrite with the
        new division algorithms in divl.S and divq.S respectively.
This commit is contained in:
Richard Henderson 2004-07-30 18:15:57 +00:00
parent 5c3c0a7a13
commit bd68d85075
4 changed files with 207 additions and 129 deletions

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@ -1,4 +1,4 @@
/* Copyright (C) 1996, 1997 Free Software Foundation, Inc.
/* Copyright (C) 1996, 1997, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth@tamu.edu>.
@ -17,13 +17,13 @@
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include "div_libc.h"
#ifdef __linux__
# include <asm/gentrap.h>
# include <asm/pal.h>
#undef FRAME
#ifdef __alpha_fix__
#define FRAME 0
#else
# include <machine/pal.h>
#define FRAME 16
#endif
.set noat
@ -32,78 +32,54 @@
.globl div
.ent div
div:
.frame sp, 0, ra
.frame sp, FRAME, ra
#if FRAME > 0
lda sp, -FRAME(sp)
#endif
#ifdef PROF
.set macro
ldgp gp, 0(pv)
lda AT, _mcount
jsr AT, (AT), _mcount
.set nomacro
.prologue 1
#else
.prologue 0
#endif
#define divisor t1
#define mask t2
#define quotient t3
#define modulus t4
#define tmp1 t5
#define tmp2 t6
#define compare t7
beq $18, $divbyzero
/* find correct sign for input to unsigned divide loop. */
negl a1, modulus # e0 :
negl a2, divisor # .. e1 :
sextl a1, a1 # e0 :
sextl a2, a2 # .. e1 :
mov zero, quotient # e0 :
mov 1, mask # .. e1 :
cmovge a1, a1, modulus # e0 :
cmovge a2, a2, divisor # .. e1 :
beq a2, $divbyzero # e1 :
unop # :
_ITOFT2 $17, $f0, 0, $18, $f1, 8
/* shift divisor left, using 3-bit shifts for 32-bit divides as we
can't overflow. Three-bit shifts will result in looping three
times less here, but can result in two loops more later. Thus
using a large shift isn't worth it (and s8addq pairs better than
a shift). */
cvtqt $f0, $f0
cvtqt $f1, $f1
divt/c $f0, $f1, $f0
cvttq/c $f0, $f0
1: cmpult divisor, modulus, compare # e0 :
s8addq divisor, zero, divisor # .. e1 :
s8addq mask, zero, mask # e0 :
bne compare, 1b # .. e1 :
_FTOIT $f0, $0, 0
/* start to go right again. */
2: addq quotient, mask, tmp2 # e1 :
srl mask, 1, mask # .. e0 :
cmpule divisor, modulus, compare # e0 :
subq modulus, divisor, tmp1 # .. e1 :
cmovne compare, tmp2, quotient # e1 :
srl divisor, 1, divisor # .. e0 :
cmovne compare, tmp1, modulus # e0 :
bne mask, 2b # .. e1 :
mull $0, $18, $1
subl $17, $1, $1
/* find correct sign for result. */
xor a1, a2, compare # e0 :
negl quotient, tmp1 # .. e1 :
negl modulus, tmp2 # e0 :
cmovlt compare, tmp1, quotient # .. e1 :
cmovlt a1, tmp2, modulus # e1 :
stl $0, 0(a0)
stl $1, 4(a0)
mov a0, v0
/* and store it away in the structure. */
stl quotient, 0(a0) # .. e0 :
mov a0, v0 # e1 :
stl modulus, 4(a0) # .. e0 :
ret # e1 :
#if FRAME > 0
lda sp, FRAME(sp)
#endif
ret
$divbyzero:
mov a0, v0
ldiq a0, GEN_INTDIV
lda a0, GEN_INTDIV
call_pal PAL_gentrap
/* if trap returns, return zero. */
stl zero, 0(v0)
stl zero, 4(v0)
#if FRAME > 0
lda sp, FRAME(sp)
#endif
ret
.end div

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@ -115,16 +115,16 @@ $fix_sign_in_ret1:
_FTOIT $f0, Q, 8
.align 3
$fix_sign_in_ret2:
mulq Q, Y, QY
stq t4, 8(sp)
ldt $f0, 0(sp)
stq t3, 0(sp)
cfi_restore ($f0)
cfi_rel_offset (t3, 0)
mulq Q, Y, QY
unop
stq t4, 8(sp)
unop
cfi_rel_offset (t4, 8)
cfi_restore ($f0)
stq t3, 0(sp)
unop
cfi_rel_offset (t3, 0)
subq QY, X, R
mov Y, SY

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@ -1,4 +1,4 @@
/* Copyright (C) 1996, 1997, 2001 Free Software Foundation, Inc.
/* Copyright (C) 1996, 1997, 2001, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson <rth@tamu.edu>.
@ -17,93 +17,195 @@
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <sysdep.h>
#include "div_libc.h"
#ifdef __linux__
# include <asm/gentrap.h>
# include <asm/pal.h>
#undef FRAME
#ifdef __alpha_fix__
#define FRAME 0
#else
# include <machine/pal.h>
#define FRAME 16
#endif
#undef X
#undef Y
#define X $17
#define Y $18
.set noat
.align 4
.globl ldiv
.ent ldiv
ldiv:
.frame sp, 0, ra
.frame sp, FRAME, ra
#if FRAME > 0
lda sp, -FRAME(sp)
#endif
#ifdef PROF
.set macro
ldgp gp, 0(pv)
lda AT, _mcount
jsr AT, (AT), _mcount
.set nomacro
.prologue 1
#else
.prologue 0
#endif
#define divisor t1
#define mask t2
#define quotient t3
#define modulus t4
#define tmp1 t5
#define tmp2 t6
#define compare t7
beq Y, $divbyzero
/* find correct sign for input to unsigned divide loop. */
mov a1, modulus # e0 :
mov a2, divisor # .. e1 :
negq a1, tmp1 # e0 :
negq a2, tmp2 # .. e1 :
mov zero, quotient # e0 :
mov 1, mask # .. e1 :
cmovlt a1, tmp1, modulus # e0 :
cmovlt a2, tmp2, divisor # .. e1 :
beq a2, $divbyzero # e1 :
unop # :
_ITOFT2 X, $f0, 0, Y, $f1, 8
/* shift divisor left. */
1: cmpult divisor, modulus, compare # e0 :
blt divisor, 2f # .. e1 :
addq divisor, divisor, divisor # e0 :
addq mask, mask, mask # .. e1 :
bne compare, 1b # e1 :
unop # :
.align 4
cvtqt $f0, $f0
cvtqt $f1, $f1
divt/c $f0, $f1, $f0
unop
/* start to go right again. */
2: addq quotient, mask, tmp2 # e1 :
srl mask, 1, mask # .. e0 :
cmpule divisor, modulus, compare # e0 :
subq modulus, divisor, tmp1 # .. e1 :
cmovne compare, tmp2, quotient # e1 :
srl divisor, 1, divisor # .. e0 :
cmovne compare, tmp1, modulus # e0 :
bne mask, 2b # .. e1 :
/* Check to see if X fit in the double as an exact value. */
sll X, (64-53), AT
sra AT, (64-53), AT
cmpeq X, AT, AT
beq AT, $x_big
/* find correct sign for result. */
xor a1, a2, compare # e0 :
negq quotient, tmp1 # .. e1 :
negq modulus, tmp2 # e0 :
cmovlt compare, tmp1, quotient # .. e1 :
cmovlt a1, tmp2, modulus # e1 :
/* If we get here, we're expecting exact results from the division.
Do nothing else besides convert and clean up. */
cvttq/c $f0, $f0
_FTOIT $f0, $0, 0
/* and store it away in the structure. */
9: stq quotient, 0(a0) # .. e0 :
mov a0, v0 # e1 :
stq modulus, 8(a0) # .. e0 :
ret # e1 :
$egress:
mulq $0, Y, $1
subq X, $1, $1
stq $0, 0($16)
stq $1, 8($16)
mov $16, $0
#if FRAME > 0
lda sp, FRAME(sp)
#endif
ret
.align 4
$x_big:
/* If we get here, X is large enough that we don't expect exact
results, and neither X nor Y got mis-translated for the fp
division. Our task is to take the fp result, figure out how
far it's off from the correct result and compute a fixup. */
#define Q v0 /* quotient */
#define R t0 /* remainder */
#define SY t1 /* scaled Y */
#define S t2 /* scalar */
#define QY t3 /* Q*Y */
/* The fixup code below can only handle unsigned values. */
or X, Y, AT
mov $31, t5
blt AT, $fix_sign_in
$fix_sign_in_ret1:
cvttq/c $f0, $f0
_FTOIT $f0, Q, 8
.align 3
$fix_sign_in_ret2:
mulq Q, Y, QY
.align 4
subq QY, X, R
mov Y, SY
mov 1, S
bgt R, $q_high
$q_high_ret:
subq X, QY, R
mov Y, SY
mov 1, S
bgt R, $q_low
$q_low_ret:
negq Q, t4
cmovlbs t5, t4, Q
br $egress
.align 4
/* The quotient that we computed was too large. We need to reduce
it by S such that Y*S >= R. Obviously the closer we get to the
correct value the better, but overshooting high is ok, as we'll
fix that up later. */
0:
addq SY, SY, SY
addq S, S, S
$q_high:
cmpult SY, R, AT
bne AT, 0b
subq Q, S, Q
unop
subq QY, SY, QY
br $q_high_ret
.align 4
/* The quotient that we computed was too small. Divide Y by the
current remainder (R) and add that to the existing quotient (Q).
The expectation, of course, is that R is much smaller than X. */
/* Begin with a shift-up loop. Compute S such that Y*S >= R. We
already have a copy of Y in SY and the value 1 in S. */
0:
addq SY, SY, SY
addq S, S, S
$q_low:
cmpult SY, R, AT
bne AT, 0b
/* Shift-down and subtract loop. Each iteration compares our scaled
Y (SY) with the remainder (R); if SY <= R then X is divisible by
Y's scalar (S) so add it to the quotient (Q). */
2: addq Q, S, t3
srl S, 1, S
cmpule SY, R, AT
subq R, SY, t4
cmovne AT, t3, Q
cmovne AT, t4, R
srl SY, 1, SY
bne S, 2b
br $q_low_ret
.align 4
$fix_sign_in:
/* If we got here, then X|Y is negative. Need to adjust everything
such that we're doing unsigned division in the fixup loop. */
/* T5 is true if result should be negative. */
xor X, Y, AT
cmplt AT, 0, t5
cmplt X, 0, AT
negq X, t0
cmovne AT, t0, X
cmplt Y, 0, AT
negq Y, t0
cmovne AT, t0, Y
blbc t5, $fix_sign_in_ret1
cvttq/c $f0, $f0
_FTOIT $f0, Q, 8
.align 3
negq Q, Q
br $fix_sign_in_ret2
$divbyzero:
mov a0, v0
lda a0, GEN_INTDIV
call_pal PAL_gentrap
/* if trap returns, return zero. */
stq zero, 0(v0)
stq zero, 8(v0)
#if FRAME > 0
lda sp, FRAME(sp)
#endif
ret
.end ldiv
weak_alias(ldiv, lldiv)
weak_alias(ldiv, imaxdiv)
.end ldiv

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@ -116,16 +116,16 @@ $fix_sign_in_ret1:
_FTOIT $f0, Q, 8
.align 3
$fix_sign_in_ret2:
mulq Q, Y, QY
stq t4, 8(sp)
ldt $f0, 0(sp)
stq t3, 0(sp)
cfi_restore ($f0)
cfi_rel_offset (t3, 0)
mulq Q, Y, QY
unop
stq t4, 8(sp)
unop
cfi_rel_offset (t4, 8)
cfi_restore ($f0)
stq t3, 0(sp)
unop
cfi_rel_offset (t3, 0)
subq QY, X, R
mov Y, SY