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author | Zack Buhman <zack@buhman.org> | 2024-04-05 17:11:47 -1000 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2024-04-09 07:43:31 -1000 |
commit | 7227c0cd506eaab5b1d89d15832cac7e05ecb412 (patch) | |
tree | 8b3e6d9d0ca14105c8ef063827e5cd18481449c1 | |
parent | c97e8977dcacb3fa8362ee28bcee75ceb01fceaa (diff) | |
download | qemu-7227c0cd506eaab5b1d89d15832cac7e05ecb412.zip qemu-7227c0cd506eaab5b1d89d15832cac7e05ecb412.tar.gz qemu-7227c0cd506eaab5b1d89d15832cac7e05ecb412.tar.bz2 |
target/sh4: Fix mac.w with saturation enabled
The saturation arithmetic logic in helper_macw is not correct.
I tested and verified this behavior on a SH7091.
Reviewd-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Zack Buhman <zack@buhman.org>
Message-Id: <20240405233802.29128-3-zack@buhman.org>
[rth: Reformat helper_macw, add a test case.]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
-rw-r--r-- | target/sh4/helper.h | 2 | ||||
-rw-r--r-- | target/sh4/op_helper.c | 28 | ||||
-rw-r--r-- | tests/tcg/sh4/Makefile.target | 3 | ||||
-rw-r--r-- | tests/tcg/sh4/test-macw.c | 61 |
4 files changed, 82 insertions, 12 deletions
diff --git a/target/sh4/helper.h b/target/sh4/helper.h index 64056e4..29011d3 100644 --- a/target/sh4/helper.h +++ b/target/sh4/helper.h @@ -12,7 +12,7 @@ DEF_HELPER_1(discard_movcal_backup, void, env) DEF_HELPER_2(ocbi, void, env, i32) DEF_HELPER_3(macl, void, env, s32, s32) -DEF_HELPER_3(macw, void, env, i32, i32) +DEF_HELPER_3(macw, void, env, s32, s32) DEF_HELPER_2(ld_fpscr, void, env, i32) diff --git a/target/sh4/op_helper.c b/target/sh4/op_helper.c index d0bae0c..99394b7 100644 --- a/target/sh4/op_helper.c +++ b/target/sh4/op_helper.c @@ -177,22 +177,28 @@ void helper_macl(CPUSH4State *env, int32_t arg0, int32_t arg1) env->mac = res; } -void helper_macw(CPUSH4State *env, uint32_t arg0, uint32_t arg1) +void helper_macw(CPUSH4State *env, int32_t arg0, int32_t arg1) { - int64_t res; + /* Inputs are already sign-extended from 16 bits. */ + int32_t mul = arg0 * arg1; - res = ((uint64_t) env->mach << 32) | env->macl; - res += (int64_t) (int16_t) arg0 *(int64_t) (int16_t) arg1; - env->mach = (res >> 32) & 0xffffffff; - env->macl = res & 0xffffffff; if (env->sr & (1u << SR_S)) { - if (res < -0x80000000) { - env->mach = 1; - env->macl = 0x80000000; - } else if (res > 0x000000007fffffff) { + /* + * In saturation arithmetic mode, the accumulator is 32-bit + * with carry. MACH is not considered during the addition + * operation nor the 32-bit saturation logic. + */ + int32_t res, macl = env->macl; + + if (sadd32_overflow(macl, mul, &res)) { + res = macl < 0 ? INT32_MIN : INT32_MAX; + /* If overflow occurs, the MACH register is set to 1. */ env->mach = 1; - env->macl = 0x7fffffff; } + env->macl = res; + } else { + /* In non-saturation arithmetic mode, the accumulator is 64-bit */ + env->mac += mul; } } diff --git a/tests/tcg/sh4/Makefile.target b/tests/tcg/sh4/Makefile.target index 9a11c10..4d09291c 100644 --- a/tests/tcg/sh4/Makefile.target +++ b/tests/tcg/sh4/Makefile.target @@ -14,3 +14,6 @@ VPATH += $(SRC_PATH)/tests/tcg/sh4 test-macl: CFLAGS += -O -g TESTS += test-macl + +test-macw: CFLAGS += -O -g +TESTS += test-macw diff --git a/tests/tcg/sh4/test-macw.c b/tests/tcg/sh4/test-macw.c new file mode 100644 index 0000000..4eceec8 --- /dev/null +++ b/tests/tcg/sh4/test-macw.c @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include <stdint.h> +#include <stdlib.h> +#include <stdio.h> + +int64_t mac_w(int64_t mac, const int16_t *a, const int16_t *b) +{ + register uint32_t macl __asm__("macl") = mac; + register uint32_t mach __asm__("mach") = mac >> 32; + + asm volatile("mac.w @%0+,@%1+" + : "+r"(a), "+r"(b), "+x"(macl), "+x"(mach)); + + return ((uint64_t)mach << 32) | macl; +} + +typedef struct { + int64_t mac; + int16_t a, b; + int64_t res[2]; +} Test; + +__attribute__((noinline)) +void test(const Test *t, int sat) +{ + int64_t res; + + if (sat) { + asm volatile("sets"); + } else { + asm volatile("clrs"); + } + res = mac_w(t->mac, &t->a, &t->b); + + if (res != t->res[sat]) { + fprintf(stderr, "%#llx + (%#x * %#x) = %#llx -- got %#llx\n", + t->mac, t->a, t->b, t->res[sat], res); + abort(); + } +} + +int main() +{ + static const Test tests[] = { + { 0, 2, 3, { 6, 6 } }, + { 0x123456787ffffffell, 2, -3, + { 0x123456787ffffff8ll, 0x123456787ffffff8ll } }, + { 0xabcdef127ffffffall, 2, 3, + { 0xabcdef1280000000ll, 0x000000017fffffffll } }, + { 0xfffffffffll, INT16_MAX, INT16_MAX, + { 0x103fff0000ll, 0xf3fff0000ll } }, + }; + + for (int i = 0; i < sizeof(tests) / sizeof(tests[0]); ++i) { + for (int j = 0; j < 2; ++j) { + test(&tests[i], j); + } + } + return 0; +} |