From: Frank Chang <frank.ch...@sifive.com> In IEEE 754-2008 spec: Invalid operation exception is signaled when doing: fusedMultiplyAdd(0, Inf, c) or fusedMultiplyAdd(Inf, 0, c) unless c is a quiet NaN; if c is a quiet NaN then it is implementation defined whether the invalid operation exception is signaled.
In RISC-V Unprivileged ISA spec: The fused multiply-add instructions must set the invalid operation exception flag when the multiplicands are Inf and zero, even when the addend is a quiet NaN. This commit set invalid operation execption flag for RISC-V when multiplicands of muladd instructions are Inf and zero. Signed-off-by: Frank Chang <frank.ch...@sifive.com> Reviewed-by: Richard Henderson <richard.hender...@linaro.org> Message-id: 20210420013150.21992-1-frank.ch...@sifive.com Signed-off-by: Alistair Francis <alistair.fran...@wdc.com> --- fpu/softfloat-specialize.c.inc | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fpu/softfloat-specialize.c.inc b/fpu/softfloat-specialize.c.inc index 9ea318f3e2..78f699d6f8 100644 --- a/fpu/softfloat-specialize.c.inc +++ b/fpu/softfloat-specialize.c.inc @@ -627,6 +627,12 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls, } else { return 1; } +#elif defined(TARGET_RISCV) + /* For RISC-V, InvalidOp is set when multiplicands are Inf and zero */ + if (infzero) { + float_raise(float_flag_invalid, status); + } + return 3; /* default NaN */ #elif defined(TARGET_XTENSA) /* * For Xtensa, the (inf,zero,nan) case sets InvalidOp and returns -- 2.31.1