152 lines
4.0 KiB
C
152 lines
4.0 KiB
C
// 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);
|
|
}
|