Although the floating point rounding mode for Microblaze is always
nearest-even, we cannot set it just once in the CPU initfn.  This is
because env->fp_status is in the part of the CPU state struct that is
zeroed on reset.

Move the call to set_float_rounding_mode() into the reset fn.

(This had no guest-visible effects because it happens that the
float_round_nearest_even enum value is 0, so when the struct was
zeroed it didn't corrupt the setting.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 target/microblaze/cpu.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/target/microblaze/cpu.c b/target/microblaze/cpu.c
index 135947ee800..6329a774331 100644
--- a/target/microblaze/cpu.c
+++ b/target/microblaze/cpu.c
@@ -201,6 +201,8 @@ static void mb_cpu_reset_hold(Object *obj, ResetType type)
 
     env->pc = cpu->cfg.base_vectors;
 
+    set_float_rounding_mode(float_round_nearest_even, &env->fp_status);
+
 #if defined(CONFIG_USER_ONLY)
     /* start in user mode with interrupts enabled.  */
     mb_cpu_write_msr(env, MSR_EE | MSR_IE | MSR_VM | MSR_UM);
@@ -311,15 +313,12 @@ static void mb_cpu_realizefn(DeviceState *dev, Error **errp)
 static void mb_cpu_initfn(Object *obj)
 {
     MicroBlazeCPU *cpu = MICROBLAZE_CPU(obj);
-    CPUMBState *env = &cpu->env;
 
     gdb_register_coprocessor(CPU(cpu), mb_cpu_gdb_read_stack_protect,
                              mb_cpu_gdb_write_stack_protect,
                              gdb_find_static_feature("microblaze-stack-protect.xml"),
                              0);
 
-    set_float_rounding_mode(float_round_nearest_even, &env->fp_status);
-
 #ifndef CONFIG_USER_ONLY
     /* Inbound IRQ and FIR lines */
     qdev_init_gpio_in(DEVICE(cpu), microblaze_cpu_set_irq, 2);
-- 
2.34.1

On 10/25/24 15:12, Peter Maydell wrote:
> Although the floating point rounding mode for Microblaze is always
> nearest-even, we cannot set it just once in the CPU initfn.  This is
> because env->fp_status is in the part of the CPU state struct that is
> zeroed on reset.
> 
> Move the call to set_float_rounding_mode() into the reset fn.
> 
> (This had no guest-visible effects because it happens that the
> float_round_nearest_even enum value is 0, so when the struct was
> zeroed it didn't corrupt the setting.)
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>   target/microblaze/cpu.c | 5 ++---
>   1 file changed, 2 insertions(+), 3 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~