diff options
| author | Nathan Froyd <froydnj@codesourcery.com> | 2012-06-07 15:04:14 +0000 |
|---|---|---|
| committer | Blue Swirl <blauwirbel@gmail.com> | 2012-08-09 18:36:19 +0000 |
| commit | f1cb0951c5298753652a73cfd8efc0b1a82f37de (patch) | |
| tree | 49b9bbe429139f35dd405a554354f53e9c1d5453 | |
| parent | 832a226b62c6bf75c57ec3ae4d6964923d2aabcd (diff) | |
MIPS: Correct FCR0 initialization
This change addresses a problem where QEMU incorrectly traps on
floating-point MADD group instructions with SIGILL, at least while
emulating MIPS32r2 processors. These instructions use the COP1X major
opcode and include ones like:
madd.d $f2,$f4,$f2,$f6
Here's Nathan's original analysis of the problem:
"QEMU essentially does:
d = find_cpu (cpu_string) // get CPU definition
fpu_init (env, d) // initialize fpu state (init FCR0, basically)
cpu_reset (env)
...and the cpu_reset call clears all interesting state that fpu_init
setup, then proceeds to reinitialize all the CP0 registers...but not
FCR0."
I have verified this change with system emulation running the GDB test
suite for the mips-sde-elf target (o32, big endian, 24Kf CPU emulated),
there were 55 progressions and no regressions.
Signed-off-by: Maciej W. Rozycki <macro@codesourcery.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
| -rw-r--r-- | target-mips/translate.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/target-mips/translate.c b/target-mips/translate.c index 4e15ee36b8..47daf8574f 100644 --- a/target-mips/translate.c +++ b/target-mips/translate.c @@ -12763,6 +12763,7 @@ void cpu_state_reset(CPUMIPSState *env) env->CP0_SRSConf3 = env->cpu_model->CP0_SRSConf3; env->CP0_SRSConf4_rw_bitmask = env->cpu_model->CP0_SRSConf4_rw_bitmask; env->CP0_SRSConf4 = env->cpu_model->CP0_SRSConf4; + env->active_fpu.fcr0 = env->cpu_model->CP1_fcr0; env->insn_flags = env->cpu_model->insn_flags; #if defined(CONFIG_USER_ONLY) |