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FPU: Set FPSCR exception summary based on individual invalid exception bits

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Rather than setting FPSCR[FX] to 1 when FPSCR[VX] transitions from 0 to 1,
this sets it when any of the individual invalid exception bits (VSXNAN,
VXISI, VXIDI, VXZDZ, VXIMZ, VXVC, VXSOFT, VXSQRT, VXCVI) transitions from
0 to 1.  This better matches the ISA and P9 behaviour.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This commit is contained in:
Paul Mackerras 2025-12-08 08:07:28 +11:00
parent fb71f62b83
commit 8a204f1058
1 changed files with 4 additions and 3 deletions
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7
fpu.vhdl
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@ -144,7 +144,7 @@ architecture behaviour of fpu is
int_result : std_ulogic;
cr_result : std_ulogic_vector(3 downto 0);
cr_mask : std_ulogic_vector(7 downto 0);
old_exc : std_ulogic_vector(4 downto 0);
old_exc : std_ulogic_vector(12 downto 0);
update_fprf : std_ulogic;
quieten_nan : std_ulogic;
nsnan_result : std_ulogic;
@ -1388,7 +1388,7 @@ begin
end if;
end if;
v.x := '0';
v.old_exc := r.fpscr(FPSCR_VX downto FPSCR_XX);
v.old_exc := r.fpscr(FPSCR_OX downto FPSCR_VXVC) & r.fpscr(FPSCR_VXSOFT downto FPSCR_VXCVI);
set_s := '1';
v.regsel := AIN_ZERO;
@ -3681,7 +3681,8 @@ begin
v.fpscr(FPSCR_FEX) := or (v.fpscr(FPSCR_VX downto FPSCR_XX) and
v.fpscr(FPSCR_VE downto FPSCR_XE));
if update_fx = '1' and
(v.fpscr(FPSCR_VX downto FPSCR_XX) and not r.old_exc) /= "00000" then
((v.fpscr(FPSCR_OX downto FPSCR_VXVC) & v.fpscr(FPSCR_VXSOFT downto FPSCR_VXCVI)) and
not r.old_exc) /= 13x"0" then
v.fpscr(FPSCR_FX) := '1';
end if;