summaryrefslogtreecommitdiff
path: root/arch/arm/lib/_udivsi3.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/lib/_udivsi3.S')
-rw-r--r--arch/arm/lib/_udivsi3.S93
1 files changed, 93 insertions, 0 deletions
diff --git a/arch/arm/lib/_udivsi3.S b/arch/arm/lib/_udivsi3.S
new file mode 100644
index 0000000..1309802
--- /dev/null
+++ b/arch/arm/lib/_udivsi3.S
@@ -0,0 +1,93 @@
+/* # 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
+ .globl __aeabi_uidiv
+ .type __aeabi_uidiv ,function
+ .align 0
+ __udivsi3:
+ __aeabi_uidiv:
+ 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
+
+.globl __aeabi_uidivmod
+__aeabi_uidivmod:
+
+ stmfd sp!, {r0, r1, ip, lr}
+ bl __aeabi_uidiv
+ ldmfd sp!, {r1, r2, ip, lr}
+ mul r3, r0, r2
+ sub r1, r1, r3
+ mov pc, lr
+
+.globl __aeabi_idivmod
+__aeabi_idivmod:
+
+ stmfd sp!, {r0, r1, ip, lr}
+ bl __aeabi_idiv
+ ldmfd sp!, {r1, r2, ip, lr}
+ mul r3, r0, r2
+ sub r1, r1, r3
+ mov pc, lr