mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
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260 lines
No EOL
6.4 KiB
C
260 lines
No EOL
6.4 KiB
C
// SPDX-License-Identifier: BSD-2-Clause
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/*
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* Copyright (c) 2014, STMicroelectronics International N.V.
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*/
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/*
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* Form ABI specifications:
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* int __aeabi_idiv(int numerator, int denominator);
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* unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator);
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*
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* typedef struct { int quot; int rem; } idiv_return;
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* typedef struct { unsigned quot; unsigned rem; } uidiv_return;
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*
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* __value_in_regs idiv_return __aeabi_idivmod(int numerator,
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* int *denominator);
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* __value_in_regs uidiv_return __aeabi_uidivmod(unsigned *numerator,
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* unsigned denominator);
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* struct qr - stores qutient/remainder to handle divmod EABI interfaces. */
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struct qr {
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unsigned q; /* computed quotient */
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unsigned r; /* computed remainder */
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unsigned q_n; /* specficies if quotient shall be negative */
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unsigned r_n; /* specficies if remainder shall be negative */
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};
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static void uint_div_qr(unsigned numerator, unsigned denominator,
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struct qr *qr);
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/* returns in R0 and R1 by tail calling an asm function */
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unsigned __aeabi_uidivmod(unsigned numerator, unsigned denominator);
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unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator);
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/* returns in R0 and R1 by tail calling an asm function */
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signed __aeabi_idivmod(signed numerator, signed denominator);
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signed __aeabi_idiv(signed numerator, signed denominator);
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/*
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* __ste_idivmod_ret_t __aeabi_idivmod(signed numerator, signed denominator)
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* Numerator and Denominator are received in R0 and R1.
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* Where __ste_idivmod_ret_t is returned in R0 and R1.
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*
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* __ste_uidivmod_ret_t __aeabi_uidivmod(unsigned numerator,
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* unsigned denominator)
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* Numerator and Denominator are received in R0 and R1.
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* Where __ste_uidivmod_ret_t is returned in R0 and R1.
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*/
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#ifdef __GNUC__
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signed ret_idivmod_values(signed quotient, signed remainder);
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unsigned ret_uidivmod_values(unsigned quotient, unsigned remainder);
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#else
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#error "Compiler not supported"
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#endif
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static void division_qr(unsigned n, unsigned p, struct qr *qr)
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{
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unsigned i = 1, q = 0;
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if (p == 0) {
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qr->r = 0xFFFFFFFF; /* division by 0 */
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return;
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}
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while ((p >> 31) == 0) {
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i = i << 1; /* count the max division steps */
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p = p << 1; /* increase p until it has maximum size*/
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}
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while (i > 0) {
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q = q << 1; /* write bit in q at index (size-1) */
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if (n >= p)
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{
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n -= p;
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q++;
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}
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p = p >> 1; /* decrease p */
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i = i >> 1; /* decrease remaining size in q */
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}
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qr->r = n;
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qr->q = q;
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}
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static void uint_div_qr(unsigned numerator, unsigned denominator, struct qr *qr)
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{
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division_qr(numerator, denominator, qr);
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/* negate quotient and/or remainder according to requester */
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if (qr->q_n)
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qr->q = -qr->q;
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if (qr->r_n)
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qr->r = -qr->r;
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}
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unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator)
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{
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struct qr qr = { .q_n = 0, .r_n = 0 };
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uint_div_qr(numerator, denominator, &qr);
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return qr.q;
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}
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unsigned __aeabi_uidivmod(unsigned numerator, unsigned denominator)
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{
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struct qr qr = { .q_n = 0, .r_n = 0 };
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uint_div_qr(numerator, denominator, &qr);
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return ret_uidivmod_values(qr.q, qr.r);
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}
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signed __aeabi_idiv(signed numerator, signed denominator)
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{
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struct qr qr = { .q_n = 0, .r_n = 0 };
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if (((numerator < 0) && (denominator > 0)) ||
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((numerator > 0) && (denominator < 0)))
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qr.q_n = 1; /* quotient shall be negate */
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if (numerator < 0) {
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numerator = -numerator;
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qr.r_n = 1; /* remainder shall be negate */
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}
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if (denominator < 0)
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denominator = -denominator;
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uint_div_qr(numerator, denominator, &qr);
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return qr.q;
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}
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signed __aeabi_idivmod(signed numerator, signed denominator)
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{
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struct qr qr = { .q_n = 0, .r_n = 0 };
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if (((numerator < 0) && (denominator > 0)) ||
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((numerator > 0) && (denominator < 0)))
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qr.q_n = 1; /* quotient shall be negate */
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if (numerator < 0) {
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numerator = -numerator;
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qr.r_n = 1; /* remainder shall be negate */
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}
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if (denominator < 0)
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denominator = -denominator;
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uint_div_qr(numerator, denominator, &qr);
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return ret_idivmod_values(qr.q, qr.r);
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}
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/* struct lqr - stores qutient/remainder to handle divmod EABI interfaces. */
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struct lqr {
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unsigned long long q; /* computed quotient */
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unsigned long long r; /* computed remainder */
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unsigned q_n; /* specficies if quotient shall be negative */
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unsigned r_n; /* specficies if remainder shall be negative */
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};
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static void ul_div_qr(unsigned long long numerator,
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unsigned long long denominator, struct lqr *qr);
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static void division_lqr(unsigned long long n, unsigned long long p,
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struct lqr *qr)
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{
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unsigned long long i = 1, q = 0;
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if (p == 0) {
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qr->r = 0xFFFFFFFFFFFFFFFFULL; /* division by 0 */
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return;
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}
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while ((p >> 63) == 0) {
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i = i << 1; /* count the max division steps */
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p = p << 1; /* increase p until it has maximum size*/
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}
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while (i > 0) {
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q = q << 1; /* write bit in q at index (size-1) */
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if (n >= p) {
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n -= p;
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q++;
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}
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p = p >> 1; /* decrease p */
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i = i >> 1; /* decrease remaining size in q */
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}
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qr->r = n;
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qr->q = q;
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}
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static void ul_div_qr(unsigned long long numerator,
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unsigned long long denominator, struct lqr *qr)
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{
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division_lqr(numerator, denominator, qr);
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/* negate quotient and/or remainder according to requester */
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if (qr->q_n)
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qr->q = -qr->q;
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if (qr->r_n)
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qr->r = -qr->r;
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}
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struct asm_ulqr {
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unsigned long long v0;
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unsigned long long v1;
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};
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/* called from assembly function __aeabi_uldivmod */
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void __ul_divmod(struct asm_ulqr *asm_ulqr);
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void __ul_divmod(struct asm_ulqr *asm_ulqr)
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{
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unsigned long long numerator = asm_ulqr->v0;
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unsigned long long denominator = asm_ulqr->v1;
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struct lqr qr = { .q_n = 0, .r_n = 0 };
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ul_div_qr(numerator, denominator, &qr);
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asm_ulqr->v0 = qr.q;
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asm_ulqr->v1 = qr.r;
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}
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struct asm_lqr {
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long long v0;
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long long v1;
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};
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/* called from assembly function __aeabi_ldivmod */
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void __l_divmod(struct asm_lqr *asm_lqr);
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void __l_divmod(struct asm_lqr *asm_lqr)
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{
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long long numerator = asm_lqr->v0;
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long long denominator = asm_lqr->v1;
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struct lqr qr = { .q_n = 0, .r_n = 0 };
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if (((numerator < 0) && (denominator > 0)) ||
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((numerator > 0) && (denominator < 0)))
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qr.q_n = 1; /* quotient shall be negate */
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if (numerator < 0) {
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numerator = -numerator;
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qr.r_n = 1; /* remainder shall be negate */
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}
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if (denominator < 0)
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denominator = -denominator;
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ul_div_qr(numerator, denominator, &qr);
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asm_lqr->v0 = qr.q;
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asm_lqr->v1 = qr.r;
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}
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#ifdef __cplusplus
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} /* extern "C" */
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#endif |