| wdenk | c609719 | 2002-11-03 00:24:07 +0000 | [diff] [blame] | 1 | /* # 1 "libgcc1.S" */ |
| 2 | @ libgcc1 routines for ARM cpu. |
| 3 | @ Division routines, written by Richard Earnshaw, (rearnsha@armltd.co.uk) |
| 4 | dividend .req r0 |
| 5 | divisor .req r1 |
| 6 | result .req r2 |
| 7 | curbit .req r3 |
| wdenk | ac6dbb8 | 2003-03-26 11:42:53 +0000 | [diff] [blame] | 8 | /* ip .req r12 */ |
| 9 | /* sp .req r13 */ |
| 10 | /* lr .req r14 */ |
| 11 | /* pc .req r15 */ |
| wdenk | c609719 | 2002-11-03 00:24:07 +0000 | [diff] [blame] | 12 | .text |
| 13 | .globl __udivsi3 |
| Wolfgang Denk | 59b4d74 | 2009-08-06 21:29:59 +0200 | [diff] [blame] | 14 | .type __udivsi3 ,function |
| 15 | .globl __aeabi_uidiv |
| 16 | .type __aeabi_uidiv ,function |
| wdenk | c609719 | 2002-11-03 00:24:07 +0000 | [diff] [blame] | 17 | .align 0 |
| Wolfgang Denk | 59b4d74 | 2009-08-06 21:29:59 +0200 | [diff] [blame] | 18 | __udivsi3: |
| 19 | __aeabi_uidiv: |
| wdenk | c609719 | 2002-11-03 00:24:07 +0000 | [diff] [blame] | 20 | cmp divisor, #0 |
| 21 | beq Ldiv0 |
| 22 | mov curbit, #1 |
| 23 | mov result, #0 |
| 24 | cmp dividend, divisor |
| 25 | bcc Lgot_result |
| 26 | Loop1: |
| 27 | @ Unless the divisor is very big, shift it up in multiples of |
| 28 | @ four bits, since this is the amount of unwinding in the main |
| 29 | @ division loop. Continue shifting until the divisor is |
| 30 | @ larger than the dividend. |
| 31 | cmp divisor, #0x10000000 |
| 32 | cmpcc divisor, dividend |
| 33 | movcc divisor, divisor, lsl #4 |
| 34 | movcc curbit, curbit, lsl #4 |
| 35 | bcc Loop1 |
| 36 | Lbignum: |
| 37 | @ For very big divisors, we must shift it a bit at a time, or |
| 38 | @ we will be in danger of overflowing. |
| 39 | cmp divisor, #0x80000000 |
| 40 | cmpcc divisor, dividend |
| 41 | movcc divisor, divisor, lsl #1 |
| 42 | movcc curbit, curbit, lsl #1 |
| 43 | bcc Lbignum |
| 44 | Loop3: |
| 45 | @ Test for possible subtractions, and note which bits |
| 46 | @ are done in the result. On the final pass, this may subtract |
| 47 | @ too much from the dividend, but the result will be ok, since the |
| 48 | @ "bit" will have been shifted out at the bottom. |
| 49 | cmp dividend, divisor |
| 50 | subcs dividend, dividend, divisor |
| 51 | orrcs result, result, curbit |
| 52 | cmp dividend, divisor, lsr #1 |
| 53 | subcs dividend, dividend, divisor, lsr #1 |
| 54 | orrcs result, result, curbit, lsr #1 |
| 55 | cmp dividend, divisor, lsr #2 |
| 56 | subcs dividend, dividend, divisor, lsr #2 |
| 57 | orrcs result, result, curbit, lsr #2 |
| 58 | cmp dividend, divisor, lsr #3 |
| 59 | subcs dividend, dividend, divisor, lsr #3 |
| 60 | orrcs result, result, curbit, lsr #3 |
| 61 | cmp dividend, #0 @ Early termination? |
| 62 | movnes curbit, curbit, lsr #4 @ No, any more bits to do? |
| 63 | movne divisor, divisor, lsr #4 |
| 64 | bne Loop3 |
| 65 | Lgot_result: |
| 66 | mov r0, result |
| Wolfgang Denk | 53677ef | 2008-05-20 16:00:29 +0200 | [diff] [blame] | 67 | mov pc, lr |
| wdenk | c609719 | 2002-11-03 00:24:07 +0000 | [diff] [blame] | 68 | Ldiv0: |
| 69 | str lr, [sp, #-4]! |
| 70 | bl __div0 (PLT) |
| 71 | mov r0, #0 @ about as wrong as it could be |
| 72 | ldmia sp!, {pc} |
| 73 | .size __udivsi3 , . - __udivsi3 |
| Wolfgang Denk | 59b4d74 | 2009-08-06 21:29:59 +0200 | [diff] [blame] | 74 | |
| 75 | .globl __aeabi_uidivmod |
| 76 | __aeabi_uidivmod: |
| 77 | |
| 78 | stmfd sp!, {r0, r1, ip, lr} |
| 79 | bl __aeabi_uidiv |
| 80 | ldmfd sp!, {r1, r2, ip, lr} |
| 81 | mul r3, r0, r2 |
| 82 | sub r1, r1, r3 |
| 83 | mov pc, lr |
| 84 | |
| 85 | .globl __aeabi_idivmod |
| 86 | __aeabi_idivmod: |
| 87 | |
| 88 | stmfd sp!, {r0, r1, ip, lr} |
| 89 | bl __aeabi_idiv |
| 90 | ldmfd sp!, {r1, r2, ip, lr} |
| 91 | mul r3, r0, r2 |
| 92 | sub r1, r1, r3 |
| 93 | mov pc, lr |