diff options
| -rw-r--r-- | tests/tcg/x86_64/Makefile.target | 1 | ||||
| -rw-r--r-- | tests/tcg/x86_64/fma.c | 109 |
2 files changed, 110 insertions, 0 deletions
diff --git a/tests/tcg/x86_64/Makefile.target b/tests/tcg/x86_64/Makefile.target index d6dff559c7..be20fc64e8 100644 --- a/tests/tcg/x86_64/Makefile.target +++ b/tests/tcg/x86_64/Makefile.target @@ -18,6 +18,7 @@ X86_64_TESTS += adox X86_64_TESTS += test-1648 X86_64_TESTS += test-2175 X86_64_TESTS += cross-modifying-code +X86_64_TESTS += fma TESTS=$(MULTIARCH_TESTS) $(X86_64_TESTS) test-x86_64 else TESTS=$(MULTIARCH_TESTS) diff --git a/tests/tcg/x86_64/fma.c b/tests/tcg/x86_64/fma.c new file mode 100644 index 0000000000..09c622ebc0 --- /dev/null +++ b/tests/tcg/x86_64/fma.c @@ -0,0 +1,109 @@ +/* + * Test some fused multiply add corner cases. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ +#include <stdio.h> +#include <stdint.h> +#include <stdbool.h> +#include <inttypes.h> + +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) + +/* + * Perform one "n * m + a" operation using the vfmadd insn and return + * the result; on return *mxcsr_p is set to the bottom 6 bits of MXCSR + * (the Flag bits). If ftz is true then we set MXCSR.FTZ while doing + * the operation. + * We print the operation and its results to stdout. + */ +static uint64_t do_fmadd(uint64_t n, uint64_t m, uint64_t a, + bool ftz, uint32_t *mxcsr_p) +{ + uint64_t r; + uint32_t mxcsr = 0; + uint32_t ftz_bit = ftz ? (1 << 15) : 0; + uint32_t saved_mxcsr = 0; + + asm volatile("stmxcsr %[saved_mxcsr]\n" + "stmxcsr %[mxcsr]\n" + "andl $0xffff7fc0, %[mxcsr]\n" + "orl %[ftz_bit], %[mxcsr]\n" + "ldmxcsr %[mxcsr]\n" + "movq %[a], %%xmm0\n" + "movq %[m], %%xmm1\n" + "movq %[n], %%xmm2\n" + /* xmm0 = xmm0 + xmm2 * xmm1 */ + "vfmadd231sd %%xmm1, %%xmm2, %%xmm0\n" + "movq %%xmm0, %[r]\n" + "stmxcsr %[mxcsr]\n" + "ldmxcsr %[saved_mxcsr]\n" + : [r] "=r" (r), [mxcsr] "=m" (mxcsr), + [saved_mxcsr] "=m" (saved_mxcsr) + : [n] "r" (n), [m] "r" (m), [a] "r" (a), + [ftz_bit] "r" (ftz_bit) + : "xmm0", "xmm1", "xmm2"); + *mxcsr_p = mxcsr & 0x3f; + printf("vfmadd132sd 0x%" PRIx64 " 0x%" PRIx64 " 0x%" PRIx64 + " = 0x%" PRIx64 " MXCSR flags 0x%" PRIx32 "\n", + n, m, a, r, *mxcsr_p); + return r; +} + +typedef struct testdata { + /* Input n, m, a */ + uint64_t n; + uint64_t m; + uint64_t a; + bool ftz; + /* Expected result */ + uint64_t expected_r; + /* Expected low 6 bits of MXCSR (the Flag bits) */ + uint32_t expected_mxcsr; +} testdata; + +static testdata tests[] = { + { 0, 0x7ff0000000000000, 0x7ff000000000aaaa, false, /* 0 * Inf + SNaN */ + 0x7ff800000000aaaa, 1 }, /* Should be QNaN and does raise Invalid */ + { 0, 0x7ff0000000000000, 0x7ff800000000aaaa, false, /* 0 * Inf + QNaN */ + 0x7ff800000000aaaa, 0 }, /* Should be QNaN and does *not* raise Invalid */ + /* + * These inputs give a result which is tiny before rounding but which + * becomes non-tiny after rounding. x86 is a "detect tininess after + * rounding" architecture, so it should give a non-denormal result and + * not set the Underflow flag (only the Precision flag for an inexact + * result). + */ + { 0x3fdfffffffffffff, 0x001fffffffffffff, 0x801fffffffffffff, false, + 0x8010000000000000, 0x20 }, + /* + * Flushing of denormal outputs to zero should also happen after + * rounding, so setting FTZ should not affect the result or the flags. + * QEMU currently does not emulate this correctly because we do the + * flush-to-zero check before rounding, so we incorrectly produce a + * zero result and set Underflow as well as Precision. + */ +#ifdef ENABLE_FAILING_TESTS + { 0x3fdfffffffffffff, 0x001fffffffffffff, 0x801fffffffffffff, true, + 0x8010000000000000, 0x20 }, /* Enabling FTZ shouldn't change flags */ +#endif +}; + +int main(void) +{ + bool passed = true; + for (int i = 0; i < ARRAY_SIZE(tests); i++) { + uint32_t mxcsr; + uint64_t r = do_fmadd(tests[i].n, tests[i].m, tests[i].a, + tests[i].ftz, &mxcsr); + if (r != tests[i].expected_r) { + printf("expected result 0x%" PRIx64 "\n", tests[i].expected_r); + passed = false; + } + if (mxcsr != tests[i].expected_mxcsr) { + printf("expected MXCSR flags 0x%x\n", tests[i].expected_mxcsr); + passed = false; + } + } + return passed ? 0 : 1; +} |