c97e8977dc
The saturation arithmetic logic in helper_macl is not correct. I tested and verified this behavior on a SH7091. Signed-off-by: Zack Buhman <zack@buhman.org> Message-Id: <20240404162641.27528-2-zack@buhman.org> [rth: Reformat helper_macl, add a test case.] Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdio.h>
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#define MACL_S_MIN (-(1ll << 47))
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#define MACL_S_MAX ((1ll << 47) - 1)
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int64_t mac_l(int64_t mac, const int32_t *a, const int32_t *b)
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{
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register uint32_t macl __asm__("macl") = mac;
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register uint32_t mach __asm__("mach") = mac >> 32;
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asm volatile("mac.l @%0+,@%1+"
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: "+r"(a), "+r"(b), "+x"(macl), "+x"(mach));
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return ((uint64_t)mach << 32) | macl;
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}
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typedef struct {
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int64_t mac;
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int32_t a, b;
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int64_t res[2];
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} Test;
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__attribute__((noinline))
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void test(const Test *t, int sat)
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{
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int64_t res;
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if (sat) {
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asm volatile("sets");
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} else {
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asm volatile("clrs");
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}
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res = mac_l(t->mac, &t->a, &t->b);
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if (res != t->res[sat]) {
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fprintf(stderr, "%#llx + (%#x * %#x) = %#llx -- got %#llx\n",
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t->mac, t->a, t->b, t->res[sat], res);
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abort();
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}
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}
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int main()
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{
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static const Test tests[] = {
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{ 0x00007fff12345678ll, INT32_MAX, INT32_MAX,
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{ 0x40007ffe12345679ll, MACL_S_MAX } },
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{ MACL_S_MIN, -1, 1,
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{ 0xffff7fffffffffffll, MACL_S_MIN } },
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{ INT64_MIN, -1, 1,
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{ INT64_MAX, MACL_S_MIN } },
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{ 0x00007fff00000000ll, INT32_MAX, INT32_MAX,
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{ 0x40007ffe00000001ll, MACL_S_MAX } },
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{ 4, 1, 2, { 6, 6 } },
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{ -4, -1, -2, { -2, -2 } },
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};
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for (int i = 0; i < sizeof(tests) / sizeof(tests[0]); ++i) {
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for (int j = 0; j < 2; ++j) {
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test(&tests[i], j);
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}
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}
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return 0;
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}
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