162306a36Sopenharmony_ci/* SPDX-License-Identifier: GPL-2.0 */ 262306a36Sopenharmony_ci#include <linux/linkage.h> 362306a36Sopenharmony_ci 462306a36Sopenharmony_ci/* 562306a36Sopenharmony_ci* modulo operation for 32 bit integers. 662306a36Sopenharmony_ci* Input : op1 in Reg r5 762306a36Sopenharmony_ci* op2 in Reg r6 862306a36Sopenharmony_ci* Output: op1 mod op2 in Reg r3 962306a36Sopenharmony_ci*/ 1062306a36Sopenharmony_ci 1162306a36Sopenharmony_ci .text 1262306a36Sopenharmony_ci .globl __modsi3 1362306a36Sopenharmony_ci .type __modsi3, @function 1462306a36Sopenharmony_ci .ent __modsi3 1562306a36Sopenharmony_ci 1662306a36Sopenharmony_ci__modsi3: 1762306a36Sopenharmony_ci .frame r1, 0, r15 1862306a36Sopenharmony_ci 1962306a36Sopenharmony_ci addik r1, r1, -16 2062306a36Sopenharmony_ci swi r28, r1, 0 2162306a36Sopenharmony_ci swi r29, r1, 4 2262306a36Sopenharmony_ci swi r30, r1, 8 2362306a36Sopenharmony_ci swi r31, r1, 12 2462306a36Sopenharmony_ci 2562306a36Sopenharmony_ci beqi r6, div_by_zero /* div_by_zero division error */ 2662306a36Sopenharmony_ci beqi r5, result_is_zero /* result is zero */ 2762306a36Sopenharmony_ci bgeid r5, r5_pos 2862306a36Sopenharmony_ci /* get the sign of the result [ depends only on the first arg] */ 2962306a36Sopenharmony_ci add r28, r5, r0 3062306a36Sopenharmony_ci rsubi r5, r5, 0 /* make r5 positive */ 3162306a36Sopenharmony_cir5_pos: 3262306a36Sopenharmony_ci bgei r6, r6_pos 3362306a36Sopenharmony_ci rsubi r6, r6, 0 /* make r6 positive */ 3462306a36Sopenharmony_cir6_pos: 3562306a36Sopenharmony_ci addik r3, r0, 0 /* clear mod */ 3662306a36Sopenharmony_ci addik r30, r0, 0 /* clear div */ 3762306a36Sopenharmony_ci addik r29, r0, 32 /* initialize the loop count */ 3862306a36Sopenharmony_ci/* first part try to find the first '1' in the r5 */ 3962306a36Sopenharmony_cidiv1: 4062306a36Sopenharmony_ci add r5, r5, r5 /* left shift logical r5 */ 4162306a36Sopenharmony_ci bgeid r5, div1 4262306a36Sopenharmony_ci addik r29, r29, -1 4362306a36Sopenharmony_cidiv2: 4462306a36Sopenharmony_ci /* left shift logical r5 get the '1' into the carry */ 4562306a36Sopenharmony_ci add r5, r5, r5 4662306a36Sopenharmony_ci addc r3, r3, r3 /* move that bit into the mod register */ 4762306a36Sopenharmony_ci rsub r31, r6, r3 /* try to subtract (r30 a r6) */ 4862306a36Sopenharmony_ci blti r31, mod_too_small 4962306a36Sopenharmony_ci /* move the r31 to mod since the result was positive */ 5062306a36Sopenharmony_ci or r3, r0, r31 5162306a36Sopenharmony_ci addik r30, r30, 1 5262306a36Sopenharmony_cimod_too_small: 5362306a36Sopenharmony_ci addik r29, r29, -1 5462306a36Sopenharmony_ci beqi r29, loop_end 5562306a36Sopenharmony_ci add r30, r30, r30 /* shift in the '1' into div */ 5662306a36Sopenharmony_ci bri div2 /* div2 */ 5762306a36Sopenharmony_ciloop_end: 5862306a36Sopenharmony_ci bgei r28, return_here 5962306a36Sopenharmony_ci brid return_here 6062306a36Sopenharmony_ci rsubi r3, r3, 0 /* negate the result */ 6162306a36Sopenharmony_cidiv_by_zero: 6262306a36Sopenharmony_ciresult_is_zero: 6362306a36Sopenharmony_ci or r3, r0, r0 /* set result to 0 [both mod as well as div are 0] */ 6462306a36Sopenharmony_cireturn_here: 6562306a36Sopenharmony_ci/* restore values of csrs and that of r3 and the divisor and the dividend */ 6662306a36Sopenharmony_ci lwi r28, r1, 0 6762306a36Sopenharmony_ci lwi r29, r1, 4 6862306a36Sopenharmony_ci lwi r30, r1, 8 6962306a36Sopenharmony_ci lwi r31, r1, 12 7062306a36Sopenharmony_ci rtsd r15, 8 7162306a36Sopenharmony_ci addik r1, r1, 16 7262306a36Sopenharmony_ci 7362306a36Sopenharmony_ci.size __modsi3, . - __modsi3 7462306a36Sopenharmony_ci.end __modsi3 75