summaryrefslogtreecommitdiff
path: root/lib_arm/_udivsi3.S
diff options
context:
space:
mode:
authorwdenk <wdenk>2002-11-03 00:24:07 +0000
committerwdenk <wdenk>2002-11-03 00:24:07 +0000
commitc609719b8d1b2dca590e0ed499016d041203e403 (patch)
tree7ea1755d80903ff972f312a249eb856061d40e15 /lib_arm/_udivsi3.S
parent5b1d713721c3ea02549940133f09236783dda1f9 (diff)
downloadu-boot-imx-c609719b8d1b2dca590e0ed499016d041203e403.zip
u-boot-imx-c609719b8d1b2dca590e0ed499016d041203e403.tar.gz
u-boot-imx-c609719b8d1b2dca590e0ed499016d041203e403.tar.bz2
Initial revision
Diffstat (limited to 'lib_arm/_udivsi3.S')
-rw-r--r--lib_arm/_udivsi3.S77
1 files changed, 77 insertions, 0 deletions
diff --git a/lib_arm/_udivsi3.S b/lib_arm/_udivsi3.S
new file mode 100644
index 0000000..19454c1
--- /dev/null
+++ b/lib_arm/_udivsi3.S
@@ -0,0 +1,77 @@
+/* # 1 "libgcc1.S" */
+@ libgcc1 routines for ARM cpu.
+@ Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk)
+dividend .req r0
+divisor .req r1
+result .req r2
+curbit .req r3
+ip .req r12
+sp .req r13
+lr .req r14
+pc .req r15
+ .text
+ .globl __udivsi3
+ .type __udivsi3 ,function
+ .align 0
+ __udivsi3 :
+ cmp divisor, #0
+ beq Ldiv0
+ mov curbit, #1
+ mov result, #0
+ cmp dividend, divisor
+ bcc Lgot_result
+Loop1:
+ @ Unless the divisor is very big, shift it up in multiples of
+ @ four bits, since this is the amount of unwinding in the main
+ @ division loop. Continue shifting until the divisor is
+ @ larger than the dividend.
+ cmp divisor, #0x10000000
+ cmpcc divisor, dividend
+ movcc divisor, divisor, lsl #4
+ movcc curbit, curbit, lsl #4
+ bcc Loop1
+Lbignum:
+ @ For very big divisors, we must shift it a bit at a time, or
+ @ we will be in danger of overflowing.
+ cmp divisor, #0x80000000
+ cmpcc divisor, dividend
+ movcc divisor, divisor, lsl #1
+ movcc curbit, curbit, lsl #1
+ bcc Lbignum
+Loop3:
+ @ Test for possible subtractions, and note which bits
+ @ are done in the result. On the final pass, this may subtract
+ @ too much from the dividend, but the result will be ok, since the
+ @ "bit" will have been shifted out at the bottom.
+ cmp dividend, divisor
+ subcs dividend, dividend, divisor
+ orrcs result, result, curbit
+ cmp dividend, divisor, lsr #1
+ subcs dividend, dividend, divisor, lsr #1
+ orrcs result, result, curbit, lsr #1
+ cmp dividend, divisor, lsr #2
+ subcs dividend, dividend, divisor, lsr #2
+ orrcs result, result, curbit, lsr #2
+ cmp dividend, divisor, lsr #3
+ subcs dividend, dividend, divisor, lsr #3
+ orrcs result, result, curbit, lsr #3
+ cmp dividend, #0 @ Early termination?
+ movnes curbit, curbit, lsr #4 @ No, any more bits to do?
+ movne divisor, divisor, lsr #4
+ bne Loop3
+Lgot_result:
+ mov r0, result
+ mov pc, lr
+Ldiv0:
+ str lr, [sp, #-4]!
+ bl __div0 (PLT)
+ mov r0, #0 @ about as wrong as it could be
+ ldmia sp!, {pc}
+ .size __udivsi3 , . - __udivsi3
+/* # 235 "libgcc1.S" */
+/* # 320 "libgcc1.S" */
+/* # 421 "libgcc1.S" */
+/* # 433 "libgcc1.S" */
+/* # 456 "libgcc1.S" */
+/* # 500 "libgcc1.S" */
+/* # 580 "libgcc1.S" */