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/*
* Copyright (c) 2017-2019, Arm Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/*
* 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 quotient/remainder to handle divmod EABI interfaces. */
struct qr {
unsigned int q; /* computed quotient */
unsigned int r; /* computed remainder */
unsigned int q_n; /* specifies if quotient shall be negative */
unsigned int r_n; /* specifies if remainder shall be negative */
};
static void uint_div_qr(unsigned int numerator, unsigned int denominator,
struct qr *qr);
/* returns in R0 and R1 by tail calling an asm function */
unsigned int __aeabi_uidivmod(unsigned int numerator, unsigned int denominator);
unsigned int __aeabi_uidiv(unsigned int numerator, unsigned int denominator);
/* returns in R0 and R1 by tail calling an asm function */
signed int __aeabi_idivmod(signed int numerator, signed int denominator);
signed int __aeabi_idiv(signed int numerator, signed int 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 int ret_idivmod_values(signed int quotient, signed int remainder);
unsigned int ret_uidivmod_values(unsigned int quotient, unsigned int remainder);
#else
#error "Compiler not supported"
#endif
static void division_qr(unsigned int n, unsigned int p, struct qr *qr)
{
unsigned int 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 int numerator, unsigned int 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 int __aeabi_uidiv(unsigned int numerator, unsigned int denominator)
{
struct qr qr = { .q_n = 0, .r_n = 0 };
uint_div_qr(numerator, denominator, &qr);
return qr.q;
}
unsigned int __aeabi_uidivmod(unsigned int numerator, unsigned int 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 int __aeabi_idiv(signed int numerator, signed int 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 int __aeabi_idivmod(signed int numerator, signed int 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);
}
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