Commit 0a87a310 authored by Tom Musta's avatar Tom Musta Committed by Peter Maydell
Browse files

softfloat: Fix float64_to_uint64_round_to_zero 



The float64_to_uint64_round_to_zero routine is incorrect.

For example, the following test pattern:

    46697351FF4AEC29 / 0x1.97351ff4aec29p+103

currently produces 8000000000000000 instead of FFFFFFFFFFFFFFFF.

This patch re-implements the routine to temporarily force the
rounding mode and use the float64_to_uint64 routine.

This contribution can be licensed under either the softfloat-2a or -2b
license.

Signed-off-by: default avatarTom Musta <tommusta@gmail.com>
Message-id: 1387397961-4894-4-git-send-email-tommusta@gmail.com
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: default avatarRichard Henderson <rth@twiddle.net>
parent 2f18bbf9

fpu/softfloat.c

+5 −7
Original line number Diff line number Diff line
@@ -6792,13 +6792,11 @@ uint64_t float64_to_uint64(float64 a STATUS_PARAM) 


uint64_t float64_to_uint64_round_to_zero (float64 a STATUS_PARAM)

{

    int64_t v;



    v = float64_val(int64_to_float64(INT64_MIN STATUS_VAR));

    v += float64_val(a);

    v = float64_to_int64_round_to_zero(make_float64(v) STATUS_VAR);



    return v - INT64_MIN;

    signed char current_rounding_mode = STATUS(float_rounding_mode);

    set_float_rounding_mode(float_round_to_zero STATUS_VAR);

    int64_t v = float64_to_uint64(a STATUS_VAR);

    set_float_rounding_mode(current_rounding_mode STATUS_VAR);

    return v;

}



#define COMPARE(s, nan_exp)                                                  \