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authorRalf Baechle <ralf@linux-mips.org>1997-01-07 02:33:00 +0000
committer <ralf@linux-mips.org>1997-01-07 02:33:00 +0000
commitbeb116954b9b7f3bb56412b2494b562f02b864b1 (patch)
tree120e997879884e1b9d93b265221b939d2ef1ade1 /arch/sparc/lib/sdiv.S
parent908d4681a1dc3792ecafbe64265783a86c4cccb6 (diff)
Import of Linux/MIPS 2.1.14
Diffstat (limited to 'arch/sparc/lib/sdiv.S')
-rw-r--r--arch/sparc/lib/sdiv.S222
1 files changed, 119 insertions, 103 deletions
diff --git a/arch/sparc/lib/sdiv.S b/arch/sparc/lib/sdiv.S
index 2fa7a9794..e0ad80b6f 100644
--- a/arch/sparc/lib/sdiv.S
+++ b/arch/sparc/lib/sdiv.S
@@ -1,4 +1,5 @@
-/* sdiv.S: This routine was taken from glibc-1.09 and is covered
+/* $Id: sdiv.S,v 1.6 1996/10/02 17:37:00 davem Exp $
+ * sdiv.S: This routine was taken from glibc-1.09 and is covered
* by the GNU Library General Public License Version 2.
*/
@@ -46,13 +47,14 @@
! compute sign of result; if neither is negative, no problem
orcc %o1, %o0, %g0 ! either negative?
bge 2f ! no, go do the divide
- xor %o1, %o0, %g6 ! compute sign in any case
+ xor %o1, %o0, %g2 ! compute sign in any case
+
tst %o1
bge 1f
- tst %o0
+ tst %o0
! %o1 is definitely negative; %o0 might also be negative
bge 2f ! if %o0 not negative...
- sub %g0, %o1, %o1 ! in any case, make %o1 nonneg
+ sub %g0, %o1, %o1 ! in any case, make %o1 nonneg
1: ! %o0 is negative, %o1 is nonnegative
sub %g0, %o0, %o0 ! make %o0 nonnegative
2:
@@ -60,22 +62,24 @@
! Ready to divide. Compute size of quotient; scale comparand.
orcc %o1, %g0, %o5
bne 1f
- mov %o0, %o3
+ mov %o0, %o3
! Divide by zero trap. If it returns, return 0 (about as
! wrong as possible, but that is what SunOS does...).
ta ST_DIV0
retl
- clr %o0
+ clr %o0
1:
cmp %o3, %o5 ! if %o1 exceeds %o0, done
blu Lgot_result ! (and algorithm fails otherwise)
- clr %o2
+ clr %o2
+
sethi %hi(1 << (32 - 4 - 1)), %g1
+
cmp %o3, %g1
blu Lnot_really_big
- clr %o4
+ clr %o4
! Here the dividend is >= 2**(31-N) or so. We must be careful here,
! as our usual N-at-a-shot divide step will cause overflow and havoc.
@@ -85,15 +89,18 @@
1:
cmp %o5, %g1
bgeu 3f
- mov 1, %g7
+ mov 1, %g7
+
sll %o5, 4, %o5
+
b 1b
- add %o4, 1, %o4
+ add %o4, 1, %o4
! Now compute %g7.
- 2: addcc %o5, %o5, %o5
+ 2:
+ addcc %o5, %o5, %o5
bcc Lnot_too_big
- add %g7, 1, %g7
+ add %g7, 1, %g7
! We get here if the %o1 overflowed while shifting.
! This means that %o3 has the high-order bit set.
@@ -101,15 +108,18 @@
sll %g1, 4, %g1 ! high order bit
srl %o5, 1, %o5 ! rest of %o5
add %o5, %g1, %o5
+
b Ldo_single_div
- sub %g7, 1, %g7
+ sub %g7, 1, %g7
Lnot_too_big:
- 3: cmp %o5, %o3
+ 3:
+ cmp %o5, %o3
blu 2b
- nop
+ nop
+
be Ldo_single_div
- nop
+ nop
/* NB: these are commented out in the V8-Sparc manual as well */
/* (I do not understand this) */
! %o5 > %o3: went too far: back up 1 step
@@ -126,19 +136,23 @@
Ldo_single_div:
subcc %g7, 1, %g7
bl Lend_regular_divide
- nop
+ nop
+
sub %o3, %o5, %o3
mov 1, %o2
+
b Lend_single_divloop
- nop
+ nop
Lsingle_divloop:
sll %o2, 1, %o2
+
bl 1f
- srl %o5, 1, %o5
+ srl %o5, 1, %o5
! %o3 >= 0
sub %o3, %o5, %o3
+
b 2f
- add %o2, 1, %o2
+ add %o2, 1, %o2
1: ! %o3 < 0
add %o3, %o5, %o3
sub %o2, 1, %o2
@@ -146,7 +160,8 @@
Lend_single_divloop:
subcc %g7, 1, %g7
bge Lsingle_divloop
- tst %o3
+ tst %o3
+
b,a Lend_regular_divide
Lnot_really_big:
@@ -154,83 +169,81 @@ Lnot_really_big:
sll %o5, 4, %o5
cmp %o5, %o3
bleu 1b
- addcc %o4, 1, %o4
+ addcc %o4, 1, %o4
+
be Lgot_result
- sub %o4, 1, %o4
+ sub %o4, 1, %o4
tst %o3 ! set up for initial iteration
Ldivloop:
sll %o2, 4, %o2
! depth 1, accumulated bits 0
bl L.1.16
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
! depth 2, accumulated bits 1
bl L.2.17
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
! depth 3, accumulated bits 3
bl L.3.19
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
! depth 4, accumulated bits 7
bl L.4.23
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (7*2+1), %o2
-
+ b 9f
+ add %o2, (7*2+1), %o2
+
L.4.23:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (7*2-1), %o2
-
-
+ b 9f
+ add %o2, (7*2-1), %o2
+
L.3.19:
! remainder is negative
addcc %o3,%o5,%o3
! depth 4, accumulated bits 5
bl L.4.21
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (5*2+1), %o2
-
+ b 9f
+ add %o2, (5*2+1), %o2
+
L.4.21:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (5*2-1), %o2
-
-
-
+ b 9f
+ add %o2, (5*2-1), %o2
+
L.2.17:
! remainder is negative
addcc %o3,%o5,%o3
! depth 3, accumulated bits 1
bl L.3.17
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
! depth 4, accumulated bits 3
bl L.4.19
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (3*2+1), %o2
-
+ b 9f
+ add %o2, (3*2+1), %o2
+
L.4.19:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (3*2-1), %o2
+ b 9f
+ add %o2, (3*2-1), %o2
L.3.17:
@@ -238,126 +251,129 @@ L.3.17:
addcc %o3,%o5,%o3
! depth 4, accumulated bits 1
bl L.4.17
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (1*2+1), %o2
-
+ b 9f
+ add %o2, (1*2+1), %o2
+
L.4.17:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (1*2-1), %o2
-
-
-
-
+ b 9f
+ add %o2, (1*2-1), %o2
+
L.1.16:
! remainder is negative
addcc %o3,%o5,%o3
! depth 2, accumulated bits -1
bl L.2.15
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
! depth 3, accumulated bits -1
bl L.3.15
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
! depth 4, accumulated bits -1
bl L.4.15
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (-1*2+1), %o2
-
+ b 9f
+ add %o2, (-1*2+1), %o2
+
L.4.15:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (-1*2-1), %o2
-
-
+ b 9f
+ add %o2, (-1*2-1), %o2
+
L.3.15:
! remainder is negative
addcc %o3,%o5,%o3
! depth 4, accumulated bits -3
bl L.4.13
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (-3*2+1), %o2
-
+ b 9f
+ add %o2, (-3*2+1), %o2
+
L.4.13:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (-3*2-1), %o2
-
-
-
+ b 9f
+ add %o2, (-3*2-1), %o2
+
L.2.15:
! remainder is negative
addcc %o3,%o5,%o3
! depth 3, accumulated bits -3
bl L.3.13
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
! depth 4, accumulated bits -5
bl L.4.11
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (-5*2+1), %o2
-
+ b 9f
+ add %o2, (-5*2+1), %o2
+
L.4.11:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (-5*2-1), %o2
-
-
+ b 9f
+ add %o2, (-5*2-1), %o2
+
L.3.13:
! remainder is negative
addcc %o3,%o5,%o3
! depth 4, accumulated bits -7
bl L.4.9
- srl %o5,1,%o5
+ srl %o5,1,%o5
! remainder is positive
subcc %o3,%o5,%o3
- b 9f
- add %o2, (-7*2+1), %o2
-
+ b 9f
+ add %o2, (-7*2+1), %o2
+
L.4.9:
! remainder is negative
addcc %o3,%o5,%o3
- b 9f
- add %o2, (-7*2-1), %o2
-
-
-
-
+ b 9f
+ add %o2, (-7*2-1), %o2
+
9:
Lend_regular_divide:
subcc %o4, 1, %o4
bge Ldivloop
- tst %o3
+ tst %o3
+
bl,a Lgot_result
! non-restoring fixup here (one instruction only!)
sub %o2, 1, %o2
-
Lgot_result:
! check to see if answer should be < 0
- tst %g6
+ tst %g2
bl,a 1f
- sub %g0, %o2, %o2
+ sub %g0, %o2, %o2
1:
retl
- mov %o2, %o0
+ mov %o2, %o0
+
+ .globl .div_patch
+.div_patch:
+ sra %o0, 0x1f, %o2
+ wr %o2, 0x0, %y
+ nop
+ nop
+ nop
+ sdivcc %o0, %o1, %o0
+ bvs,a 1f
+ xnor %o0, %g0, %o0
+1: retl
+ nop