| // SPDX-License-Identifier: BSD-2-Clause |
| /* |
| * Copyright (c) 2014, STMicroelectronics International N.V. |
| */ |
| |
| /* |
| * Form ABI specifications: |
| * int __aeabi_idiv(int numerator, int denominator); |
| * unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator); |
| * |
| * typedef struct { int quot; int rem; } idiv_return; |
| * typedef struct { unsigned quot; unsigned rem; } uidiv_return; |
| * |
| * __value_in_regs idiv_return __aeabi_idivmod(int numerator, |
| * int *denominator); |
| * __value_in_regs uidiv_return __aeabi_uidivmod(unsigned *numerator, |
| * unsigned denominator); |
| */ |
| |
| /* struct qr - stores qutient/remainder to handle divmod EABI interfaces. */ |
| struct qr { |
| unsigned q; /* computed quotient */ |
| unsigned r; /* computed remainder */ |
| unsigned q_n; /* specficies if quotient shall be negative */ |
| unsigned r_n; /* specficies if remainder shall be negative */ |
| }; |
| |
| static void uint_div_qr(unsigned numerator, unsigned denominator, |
| struct qr *qr); |
| |
| /* returns in R0 and R1 by tail calling an asm function */ |
| unsigned __aeabi_uidivmod(unsigned numerator, unsigned denominator); |
| |
| unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator); |
| |
| /* returns in R0 and R1 by tail calling an asm function */ |
| signed __aeabi_idivmod(signed numerator, signed denominator); |
| |
| signed __aeabi_idiv(signed numerator, signed denominator); |
| |
| /* |
| * __ste_idivmod_ret_t __aeabi_idivmod(signed numerator, signed denominator) |
| * Numerator and Denominator are received in R0 and R1. |
| * Where __ste_idivmod_ret_t is returned in R0 and R1. |
| * |
| * __ste_uidivmod_ret_t __aeabi_uidivmod(unsigned numerator, |
| * unsigned denominator) |
| * Numerator and Denominator are received in R0 and R1. |
| * Where __ste_uidivmod_ret_t is returned in R0 and R1. |
| */ |
| #ifdef __GNUC__ |
| signed ret_idivmod_values(signed quotient, signed remainder); |
| unsigned ret_uidivmod_values(unsigned quotient, unsigned remainder); |
| #else |
| #error "Compiler not supported" |
| #endif |
| |
| static void division_qr(unsigned n, unsigned p, struct qr *qr) |
| { |
| unsigned i = 1, q = 0; |
| if (p == 0) { |
| qr->r = 0xFFFFFFFF; /* division by 0 */ |
| return; |
| } |
| |
| while ((p >> 31) == 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 uint_div_qr(unsigned numerator, unsigned denominator, struct qr *qr) |
| { |
| |
| division_qr(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; |
| } |
| |
| unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator) |
| { |
| struct qr qr = { .q_n = 0, .r_n = 0 }; |
| |
| uint_div_qr(numerator, denominator, &qr); |
| |
| return qr.q; |
| } |
| |
| unsigned __aeabi_uidivmod(unsigned numerator, unsigned denominator) |
| { |
| struct qr qr = { .q_n = 0, .r_n = 0 }; |
| |
| uint_div_qr(numerator, denominator, &qr); |
| |
| return ret_uidivmod_values(qr.q, qr.r); |
| } |
| |
| signed __aeabi_idiv(signed numerator, signed denominator) |
| { |
| struct qr 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; |
| |
| uint_div_qr(numerator, denominator, &qr); |
| |
| return qr.q; |
| } |
| |
| signed __aeabi_idivmod(signed numerator, signed denominator) |
| { |
| struct qr 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; |
| |
| uint_div_qr(numerator, denominator, &qr); |
| |
| return ret_idivmod_values(qr.q, qr.r); |
| } |