diff options
Diffstat (limited to 'lib_arm/_udivsi3.S')
| -rw-r--r-- | lib_arm/_udivsi3.S | 77 |
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" */ |