From: Max Chou <[email protected]> According to Intel's x87 FPU specification (Table 8-10, Vol. 1), arithmetic operations on operands in unsupported formats (including pseudo-NaNs) must return the QNaN floating-point indefinite value.
The helper functions for FPATAN, FYL2XP1, and FYL2X incorrectly check for signaling NaN before checking for invalid encodings. This causes pseudo-NaNs to be treated as valid signaling NaNs and silenced, rather than being rejected as unsupported formats. Reorder the checks to test floatx80_invalid_encoding before floatx80_is_signaling_nan, matching the correct behavior already implemented in helper_fscale. Signed-off-by: Max Chou <[email protected]> Reviewed-by: Richard Henderson <[email protected]> Reviewed-by: Chao Liu <[email protected]> Signed-off-by: Richard Henderson <[email protected]> Message-ID: <[email protected]> --- target/i386/tcg/fpu_helper.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/target/i386/tcg/fpu_helper.c b/target/i386/tcg/fpu_helper.c index b3b23823fd..37c83ded38 100644 --- a/target/i386/tcg/fpu_helper.c +++ b/target/i386/tcg/fpu_helper.c @@ -1377,16 +1377,16 @@ void helper_fpatan(CPUX86State *env) int32_t arg1_exp = extractFloatx80Exp(ST1); bool arg1_sign = extractFloatx80Sign(ST1); - if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { + if (floatx80_invalid_encoding(ST0, &env->fp_status) || + floatx80_invalid_encoding(ST1, &env->fp_status)) { + float_raise(float_flag_invalid, &env->fp_status); + ST1 = floatx80_default_nan(&env->fp_status); + } else if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 = floatx80_silence_nan(ST0, &env->fp_status); } else if (floatx80_is_signaling_nan(ST1, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 = floatx80_silence_nan(ST1, &env->fp_status); - } else if (floatx80_invalid_encoding(ST0, &env->fp_status) || - floatx80_invalid_encoding(ST1, &env->fp_status)) { - float_raise(float_flag_invalid, &env->fp_status); - ST1 = floatx80_default_nan(&env->fp_status); } else if (floatx80_is_any_nan(ST0)) { ST1 = ST0; } else if (floatx80_is_any_nan(ST1)) { @@ -2061,16 +2061,16 @@ void helper_fyl2xp1(CPUX86State *env) int32_t arg1_exp = extractFloatx80Exp(ST1); bool arg1_sign = extractFloatx80Sign(ST1); - if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { + if (floatx80_invalid_encoding(ST0, &env->fp_status) || + floatx80_invalid_encoding(ST1, &env->fp_status)) { + float_raise(float_flag_invalid, &env->fp_status); + ST1 = floatx80_default_nan(&env->fp_status); + } else if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 = floatx80_silence_nan(ST0, &env->fp_status); } else if (floatx80_is_signaling_nan(ST1, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 = floatx80_silence_nan(ST1, &env->fp_status); - } else if (floatx80_invalid_encoding(ST0, &env->fp_status) || - floatx80_invalid_encoding(ST1, &env->fp_status)) { - float_raise(float_flag_invalid, &env->fp_status); - ST1 = floatx80_default_nan(&env->fp_status); } else if (floatx80_is_any_nan(ST0)) { ST1 = ST0; } else if (floatx80_is_any_nan(ST1)) { @@ -2159,16 +2159,16 @@ void helper_fyl2x(CPUX86State *env) int32_t arg1_exp = extractFloatx80Exp(ST1); bool arg1_sign = extractFloatx80Sign(ST1); - if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { + if (floatx80_invalid_encoding(ST0, &env->fp_status) || + floatx80_invalid_encoding(ST1, &env->fp_status)) { + float_raise(float_flag_invalid, &env->fp_status); + ST1 = floatx80_default_nan(&env->fp_status); + } else if (floatx80_is_signaling_nan(ST0, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 = floatx80_silence_nan(ST0, &env->fp_status); } else if (floatx80_is_signaling_nan(ST1, &env->fp_status)) { float_raise(float_flag_invalid, &env->fp_status); ST1 = floatx80_silence_nan(ST1, &env->fp_status); - } else if (floatx80_invalid_encoding(ST0, &env->fp_status) || - floatx80_invalid_encoding(ST1, &env->fp_status)) { - float_raise(float_flag_invalid, &env->fp_status); - ST1 = floatx80_default_nan(&env->fp_status); } else if (floatx80_is_any_nan(ST0)) { ST1 = ST0; } else if (floatx80_is_any_nan(ST1)) { -- 2.43.0
