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297 lines
6.8 KiB
C
297 lines
6.8 KiB
C
/*
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* ARM generic helpers for various arithmetical operations.
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*
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* This code is licensed under the GNU GPL v2 or later.
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "qemu/osdep.h"
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#include "cpu.h"
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#include "exec/helper-proto.h"
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#include "qemu/crc32c.h"
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#include <zlib.h> /* for crc32 */
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/*
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* Note that signed overflow is undefined in C. The following routines are
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* careful to use unsigned types where modulo arithmetic is required.
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* Failure to do so _will_ break on newer gcc.
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*/
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/* Signed saturating arithmetic. */
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/* Perform 16-bit signed saturating addition. */
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static inline uint16_t add16_sat(uint16_t a, uint16_t b)
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{
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uint16_t res;
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res = a + b;
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if (((res ^ a) & 0x8000) && !((a ^ b) & 0x8000)) {
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if (a & 0x8000) {
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res = 0x8000;
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} else {
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res = 0x7fff;
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}
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}
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return res;
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}
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/* Perform 8-bit signed saturating addition. */
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static inline uint8_t add8_sat(uint8_t a, uint8_t b)
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{
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uint8_t res;
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res = a + b;
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if (((res ^ a) & 0x80) && !((a ^ b) & 0x80)) {
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if (a & 0x80) {
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res = 0x80;
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} else {
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res = 0x7f;
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}
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}
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return res;
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}
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/* Perform 16-bit signed saturating subtraction. */
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static inline uint16_t sub16_sat(uint16_t a, uint16_t b)
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{
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uint16_t res;
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res = a - b;
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if (((res ^ a) & 0x8000) && ((a ^ b) & 0x8000)) {
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if (a & 0x8000) {
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res = 0x8000;
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} else {
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res = 0x7fff;
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}
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}
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return res;
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}
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/* Perform 8-bit signed saturating subtraction. */
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static inline uint8_t sub8_sat(uint8_t a, uint8_t b)
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{
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uint8_t res;
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res = a - b;
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if (((res ^ a) & 0x80) && ((a ^ b) & 0x80)) {
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if (a & 0x80) {
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res = 0x80;
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} else {
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res = 0x7f;
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}
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}
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return res;
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}
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#define ADD16(a, b, n) RESULT(add16_sat(a, b), n, 16);
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#define SUB16(a, b, n) RESULT(sub16_sat(a, b), n, 16);
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#define ADD8(a, b, n) RESULT(add8_sat(a, b), n, 8);
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#define SUB8(a, b, n) RESULT(sub8_sat(a, b), n, 8);
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#define PFX q
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#include "op_addsub.c.inc"
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/* Unsigned saturating arithmetic. */
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static inline uint16_t add16_usat(uint16_t a, uint16_t b)
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{
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uint16_t res;
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res = a + b;
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if (res < a) {
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res = 0xffff;
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}
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return res;
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}
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static inline uint16_t sub16_usat(uint16_t a, uint16_t b)
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{
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if (a > b) {
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return a - b;
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} else {
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return 0;
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}
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}
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static inline uint8_t add8_usat(uint8_t a, uint8_t b)
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{
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uint8_t res;
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res = a + b;
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if (res < a) {
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res = 0xff;
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}
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return res;
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}
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static inline uint8_t sub8_usat(uint8_t a, uint8_t b)
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{
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if (a > b) {
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return a - b;
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} else {
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return 0;
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}
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}
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#define ADD16(a, b, n) RESULT(add16_usat(a, b), n, 16);
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#define SUB16(a, b, n) RESULT(sub16_usat(a, b), n, 16);
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#define ADD8(a, b, n) RESULT(add8_usat(a, b), n, 8);
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#define SUB8(a, b, n) RESULT(sub8_usat(a, b), n, 8);
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#define PFX uq
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#include "op_addsub.c.inc"
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/* Signed modulo arithmetic. */
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#define SARITH16(a, b, n, op) do { \
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int32_t sum; \
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sum = (int32_t)(int16_t)(a) op (int32_t)(int16_t)(b); \
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RESULT(sum, n, 16); \
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if (sum >= 0) \
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ge |= 3 << (n * 2); \
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} while (0)
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#define SARITH8(a, b, n, op) do { \
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int32_t sum; \
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sum = (int32_t)(int8_t)(a) op (int32_t)(int8_t)(b); \
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RESULT(sum, n, 8); \
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if (sum >= 0) \
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ge |= 1 << n; \
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} while (0)
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#define ADD16(a, b, n) SARITH16(a, b, n, +)
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#define SUB16(a, b, n) SARITH16(a, b, n, -)
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#define ADD8(a, b, n) SARITH8(a, b, n, +)
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#define SUB8(a, b, n) SARITH8(a, b, n, -)
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#define PFX s
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#define ARITH_GE
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#include "op_addsub.c.inc"
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/* Unsigned modulo arithmetic. */
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#define ADD16(a, b, n) do { \
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uint32_t sum; \
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sum = (uint32_t)(uint16_t)(a) + (uint32_t)(uint16_t)(b); \
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RESULT(sum, n, 16); \
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if ((sum >> 16) == 1) \
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ge |= 3 << (n * 2); \
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} while (0)
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#define ADD8(a, b, n) do { \
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uint32_t sum; \
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sum = (uint32_t)(uint8_t)(a) + (uint32_t)(uint8_t)(b); \
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RESULT(sum, n, 8); \
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if ((sum >> 8) == 1) \
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ge |= 1 << n; \
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} while (0)
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#define SUB16(a, b, n) do { \
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uint32_t sum; \
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sum = (uint32_t)(uint16_t)(a) - (uint32_t)(uint16_t)(b); \
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RESULT(sum, n, 16); \
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if ((sum >> 16) == 0) \
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ge |= 3 << (n * 2); \
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} while (0)
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#define SUB8(a, b, n) do { \
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uint32_t sum; \
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sum = (uint32_t)(uint8_t)(a) - (uint32_t)(uint8_t)(b); \
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RESULT(sum, n, 8); \
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if ((sum >> 8) == 0) \
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ge |= 1 << n; \
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} while (0)
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#define PFX u
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#define ARITH_GE
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#include "op_addsub.c.inc"
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/* Halved signed arithmetic. */
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#define ADD16(a, b, n) \
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RESULT(((int32_t)(int16_t)(a) + (int32_t)(int16_t)(b)) >> 1, n, 16)
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#define SUB16(a, b, n) \
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RESULT(((int32_t)(int16_t)(a) - (int32_t)(int16_t)(b)) >> 1, n, 16)
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#define ADD8(a, b, n) \
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RESULT(((int32_t)(int8_t)(a) + (int32_t)(int8_t)(b)) >> 1, n, 8)
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#define SUB8(a, b, n) \
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RESULT(((int32_t)(int8_t)(a) - (int32_t)(int8_t)(b)) >> 1, n, 8)
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#define PFX sh
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#include "op_addsub.c.inc"
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/* Halved unsigned arithmetic. */
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#define ADD16(a, b, n) \
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RESULT(((uint32_t)(uint16_t)(a) + (uint32_t)(uint16_t)(b)) >> 1, n, 16)
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#define SUB16(a, b, n) \
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RESULT(((uint32_t)(uint16_t)(a) - (uint32_t)(uint16_t)(b)) >> 1, n, 16)
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#define ADD8(a, b, n) \
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RESULT(((uint32_t)(uint8_t)(a) + (uint32_t)(uint8_t)(b)) >> 1, n, 8)
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#define SUB8(a, b, n) \
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RESULT(((uint32_t)(uint8_t)(a) - (uint32_t)(uint8_t)(b)) >> 1, n, 8)
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#define PFX uh
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#include "op_addsub.c.inc"
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static inline uint8_t do_usad(uint8_t a, uint8_t b)
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{
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if (a > b) {
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return a - b;
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} else {
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return b - a;
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}
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}
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/* Unsigned sum of absolute byte differences. */
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uint32_t HELPER(usad8)(uint32_t a, uint32_t b)
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{
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uint32_t sum;
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sum = do_usad(a, b);
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sum += do_usad(a >> 8, b >> 8);
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sum += do_usad(a >> 16, b >> 16);
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sum += do_usad(a >> 24, b >> 24);
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return sum;
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}
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/* For ARMv6 SEL instruction. */
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uint32_t HELPER(sel_flags)(uint32_t flags, uint32_t a, uint32_t b)
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{
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uint32_t mask;
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mask = 0;
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if (flags & 1) {
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mask |= 0xff;
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}
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if (flags & 2) {
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mask |= 0xff00;
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}
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if (flags & 4) {
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mask |= 0xff0000;
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}
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if (flags & 8) {
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mask |= 0xff000000;
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}
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return (a & mask) | (b & ~mask);
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}
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/*
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* CRC helpers.
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* The upper bytes of val (above the number specified by 'bytes') must have
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* been zeroed out by the caller.
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*/
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uint32_t HELPER(crc32)(uint32_t acc, uint32_t val, uint32_t bytes)
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{
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uint8_t buf[4];
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stl_le_p(buf, val);
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/* zlib crc32 converts the accumulator and output to one's complement. */
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return crc32(acc ^ 0xffffffff, buf, bytes) ^ 0xffffffff;
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}
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uint32_t HELPER(crc32c)(uint32_t acc, uint32_t val, uint32_t bytes)
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{
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uint8_t buf[4];
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stl_le_p(buf, val);
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/* Linux crc32c converts the output to one's complement. */
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return crc32c(acc, buf, bytes) ^ 0xffffffff;
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}
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