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abbeb42c17
Changing the sign before rounding affects the correctness of the asymmetric rouding modes: float_round_up and float_round_down. Reported-by: WANG Rui <wangrui@loongson.cn> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
38 lines
809 B
C
38 lines
809 B
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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#include <stdio.h>
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#include <math.h>
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#include <fenv.h>
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union U {
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double d;
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unsigned long long l;
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};
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union U x = { .l = 0x4ff0000000000000ULL };
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union U y = { .l = 0x2ff0000000000000ULL };
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union U r;
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int main()
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{
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#ifdef FE_DOWNWARD
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fesetround(FE_DOWNWARD);
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#if defined(__loongarch__)
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asm("fnmsub.d %0, %1, %1, %2" : "=f"(r.d) : "f"(x.d), "f"(y.d));
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#elif defined(__powerpc64__)
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asm("fnmsub %0,%1,%1,%2" : "=f"(r.d) : "f"(x.d), "f"(y.d));
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#elif defined(__s390x__) && 0 /* need -march=z14 */
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asm("vfnms %0,%1,%1,%2,0,3" : "=f"(r.d) : "f"(x.d), "f"(y.d));
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#else
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r.d = -fma(x.d, x.d, -y.d);
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#endif
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if (r.l != 0xdfefffffffffffffULL) {
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printf("r = %.18a (%016llx)\n", r.d, r.l);
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return 1;
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}
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#endif
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return 0;
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}
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