| // SPDX-License-Identifier: BSD-2-Clause |
| /* |
| * Copyright (c) 2015, STMicroelectronics International N.V. |
| */ |
| |
| /* struct lqr - stores qutient/remainder to handle divmod EABI interfaces. */ |
| struct lqr { |
| unsigned long long q; /* computed quotient */ |
| unsigned long long r; /* computed remainder */ |
| unsigned q_n; /* specficies if quotient shall be negative */ |
| unsigned r_n; /* specficies if remainder shall be negative */ |
| }; |
| |
| static void ul_div_qr(unsigned long long numerator, |
| unsigned long long denominator, struct lqr *qr); |
| |
| |
| static void division_lqr(unsigned long long n, unsigned long long p, |
| struct lqr *qr) |
| { |
| unsigned long long i = 1, q = 0; |
| if (p == 0) { |
| qr->r = 0xFFFFFFFFFFFFFFFFULL; /* division by 0 */ |
| return; |
| } |
| |
| while ((p >> 63) == 0) { |
| i = i << 1; /* count the max division steps */ |
| p = p << 1; /* increase p until it has maximum size*/ |
| } |
| |
| while (i > 0) { |
| q = q << 1; /* write bit in q at index (size-1) */ |
| if (n >= p) { |
| n -= p; |
| q++; |
| } |
| p = p >> 1; /* decrease p */ |
| i = i >> 1; /* decrease remaining size in q */ |
| } |
| qr->r = n; |
| qr->q = q; |
| } |
| |
| static void ul_div_qr(unsigned long long numerator, |
| unsigned long long denominator, struct lqr *qr) |
| { |
| |
| division_lqr(numerator, denominator, qr); |
| |
| /* negate quotient and/or remainder according to requester */ |
| if (qr->q_n) |
| qr->q = -qr->q; |
| if (qr->r_n) |
| qr->r = -qr->r; |
| } |
| |
| struct asm_ulqr { |
| unsigned long long v0; |
| unsigned long long v1; |
| }; |
| |
| /* called from assembly function __aeabi_uldivmod */ |
| void __ul_divmod(struct asm_ulqr *asm_ulqr); |
| void __ul_divmod(struct asm_ulqr *asm_ulqr) |
| { |
| unsigned long long numerator = asm_ulqr->v0; |
| unsigned long long denominator = asm_ulqr->v1; |
| struct lqr qr = { .q_n = 0, .r_n = 0 }; |
| |
| ul_div_qr(numerator, denominator, &qr); |
| |
| asm_ulqr->v0 = qr.q; |
| asm_ulqr->v1 = qr.r; |
| } |
| |
| struct asm_lqr { |
| long long v0; |
| long long v1; |
| }; |
| |
| /* called from assembly function __aeabi_ldivmod */ |
| void __l_divmod(struct asm_lqr *asm_lqr); |
| void __l_divmod(struct asm_lqr *asm_lqr) |
| { |
| long long numerator = asm_lqr->v0; |
| long long denominator = asm_lqr->v1; |
| struct lqr qr = { .q_n = 0, .r_n = 0 }; |
| |
| if (((numerator < 0) && (denominator > 0)) || |
| ((numerator > 0) && (denominator < 0))) |
| qr.q_n = 1; /* quotient shall be negate */ |
| if (numerator < 0) { |
| numerator = -numerator; |
| qr.r_n = 1; /* remainder shall be negate */ |
| } |
| if (denominator < 0) |
| denominator = -denominator; |
| |
| ul_div_qr(numerator, denominator, &qr); |
| |
| asm_lqr->v0 = qr.q; |
| asm_lqr->v1 = qr.r; |
| } |