-/* Copyright (C) 1996 Free Software Foundation, Inc.
- Contributed by Richard Henderson (rth@tamu.edu)
-
+/* Copyright (C) 1996-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
+ Contributed by Richard Henderson <rth@tamu.edu>.
The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Library General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Library General Public License for more details.
-
- You should have received a copy of the GNU Library General Public
- License along with the GNU C Library; see the file COPYING.LIB. If
- not, write to the Free Software Foundation, Inc., 675 Mass Ave,
- Cambridge, MA 02139, USA. */
+ Lesser General Public License for more details.
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library. If not, see
+ <http://www.gnu.org/licenses/>. */
-#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 dividend t0
-#define divisor t1
-#define mask t2
-#define quotient t3
-#define modulus t4
-#define tmp1 t5
-#define tmp2 t6
-#define compare t7
-
- /* find correct sign for input to unsigned divide loop. */
- mov a1, dividend # e0 :
- mov a2, divisor # .. e1 :
- negq a1, tmp1 # e0 :
- negq a2, tmp2 # .. e1 :
- cmovlt a1, tmp1, dividend # e0 :
- cmovlt a2, tmp2, divisor # .. e1 :
- beq a2, $divbyzero # e1 :
- unop # :
-
- /* 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 # :
-
- /* 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 :
-
- /* 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 :
-
- /* and store it away in the structure. */
-9: stq quotient, 0(a0) # .. e0 :
- mov a0, v0 # e1 :
- stq modulus, 8(a0) # .. e0 :
- ret # e1 :
+ beq Y, $divbyzero
+ excb
+ mf_fpcr $f10
+
+ _ITOFT2 X, $f0, 0, Y, $f1, 8
+
+ .align 4
+ cvtqt $f0, $f0
+ cvtqt $f1, $f1
+ divt/c $f0, $f1, $f0
+ unop
+
+ /* 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
+
+ /* If we get here, we're expecting exact results from the division.
+ Do nothing else besides convert and clean up. */
+ cvttq/c $f0, $f0
+ excb
+ mt_fpcr $f10
+ _FTOIT $f0, $0, 0
+
+$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 $f0, Q, 8
+$fix_sign_in_ret2:
+ mulq Q, Y, QY
+ excb
+ mt_fpcr $f10
+
+ .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
+ .end ldiv
-weak_alias(ldiv, lldiv)
+weak_alias (ldiv, lldiv)
+weak_alias (ldiv, imaxdiv)
projects / thirdparty / glibc.git / blobdiff