diff options
| author | Peter Maydell <peter.maydell@linaro.org> | 2024-11-05 10:09:56 +0000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2024-11-05 10:09:56 +0000 |
| commit | 8403a5015c5d5ef01792dc5ebf3c10aa5594931f (patch) | |
| tree | 44f42f8d1d0d2b40241b77e20590bc3e2bd5d1df /target | |
| parent | 62d39b28ef4e7ad41a3ef3e37037615de6dfc194 (diff) | |
target/alpha: Explicitly set 2-NaN propagation rule
Set the NaN propagation rule explicitly for the float_status word
used in this target.
This is a no-behaviour-change commit, so we retain the existing
behaviour of x87-style pick-largest-significand NaN propagation.
This is however not the architecturally correct handling, so we leave
a TODO note to that effect.
We also leave a TODO note pointing out that all this code in the cpu
initfn (including the existing setting up of env->flags and the FPCR)
should be in a currently non-existent CPU reset function.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20241025141254.2141506-17-peter.maydell@linaro.org
Diffstat (limited to 'target')
| -rw-r--r-- | target/alpha/cpu.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/target/alpha/cpu.c b/target/alpha/cpu.c index 9db1dffc03..5d75c941f7 100644 --- a/target/alpha/cpu.c +++ b/target/alpha/cpu.c @@ -24,6 +24,7 @@ #include "qemu/qemu-print.h" #include "cpu.h" #include "exec/exec-all.h" +#include "fpu/softfloat.h" static void alpha_cpu_set_pc(CPUState *cs, vaddr value) @@ -187,7 +188,17 @@ static void alpha_cpu_initfn(Object *obj) { CPUAlphaState *env = cpu_env(CPU(obj)); + /* TODO all this should be done in reset, not init */ + env->lock_addr = -1; + + /* + * TODO: this is incorrect. The Alpha Architecture Handbook version 4 + * describes NaN propagation in section 4.7.10.4. We should prefer + * the operand in Fb (whether it is a QNaN or an SNaN), then the + * operand in Fa. That is float_2nan_prop_ba. + */ + set_float_2nan_prop_rule(float_2nan_prop_x87, &env->fp_status); #if defined(CONFIG_USER_ONLY) env->flags = ENV_FLAG_PS_USER | ENV_FLAG_FEN; cpu_alpha_store_fpcr(env, (uint64_t)(FPCR_INVD | FPCR_DZED | FPCR_OVFD |