1#include <linux/linkage.h> 2 3/* 4 * Unsigned modulo operation for 32 bit integers. 5 * Input : op1 in Reg r5 6 * op2 in Reg r6 7 * Output: op1 mod op2 in Reg r3 8 */ 9 10 .text 11 .globl __umodsi3 12 .type __umodsi3, @function 13 .ent __umodsi3 14 15__umodsi3: 16 .frame r1, 0, r15 17 18 addik r1, r1, -12 19 swi r29, r1, 0 20 swi r30, r1, 4 21 swi r31, r1, 8 22 23 beqi r6, div_by_zero /* div_by_zero - division error */ 24 beqid r5, result_is_zero /* result is zero */ 25 addik r3, r0, 0 /* clear div */ 26 addik r30, r0, 0 /* clear mod */ 27 addik r29, r0, 32 /* initialize the loop count */ 28 29/* check if r6 and r5 are equal /* if yes, return 0 */ 30 rsub r18, r5, r6 31 beqi r18, return_here 32 33/* check if (uns)r6 is greater than (uns)r5. in that case, just return r5 */ 34 xor r18, r5, r6 35 bgeid r18, 16 36 addik r3, r5, 0 37 blti r6, return_here 38 bri $lcheckr6 39 rsub r18, r5, r6 /* microblazecmp */ 40 bgti r18, return_here 41 42/* if r6 [bit 31] is set, then return result as r5-r6 */ 43$lcheckr6: 44 bgtid r6, div0 45 addik r3, r0, 0 46 addik r18, r0, 0x7fffffff 47 and r5, r5, r18 48 and r6, r6, r18 49 brid return_here 50 rsub r3, r6, r5 51/* first part: try to find the first '1' in the r5 */ 52div0: 53 blti r5, div2 54div1: 55 add r5, r5, r5 /* left shift logical r5 */ 56 bgeid r5, div1 57 addik r29, r29, -1 58div2: 59 /* left shift logical r5 get the '1' into the carry */ 60 add r5, r5, r5 61 addc r3, r3, r3 /* move that bit into the mod register */ 62 rsub r31, r6, r3 /* try to subtract (r3 a r6) */ 63 blti r31, mod_too_small 64 /* move the r31 to mod since the result was positive */ 65 or r3, r0, r31 66 addik r30, r30, 1 67mod_too_small: 68 addik r29, r29, -1 69 beqi r29, loop_end 70 add r30, r30, r30 /* shift in the '1' into div */ 71 bri div2 /* div2 */ 72loop_end: 73 bri return_here 74div_by_zero: 75result_is_zero: 76 or r3, r0, r0 /* set result to 0 */ 77return_here: 78/* restore values of csrs and that of r3 and the divisor and the dividend */ 79 lwi r29, r1, 0 80 lwi r30, r1, 4 81 lwi r31, r1, 8 82 rtsd r15, 8 83 addik r1, r1, 12 84 85.size __umodsi3, . - __umodsi3 86.end __umodsi3 87