On 8/2/23 17:55, Keith Packard via wrote:
Add helpers for reading/writing the 68881 FPSR register so that
changes in floating point exception state can be seen by the
application.
Signed-off-by: Keith Packard <kei...@keithp.com>
---
target/m68k/cpu.h | 2 ++
target/m68k/fpu_helper.c | 72 ++++++++++++++++++++++++++++++++++++++++
target/m68k/helper.c | 4 +--
target/m68k/helper.h | 2 ++
target/m68k/translate.c | 4 +--
5 files changed, 80 insertions(+), 4 deletions(-)
Good catch. Mostly ok.
+static inline int cpu_m68k_exceptbits_from_host(int host_bits)
...
+static inline int cpu_m68k_exceptbits_to_host(int target_bits)
No need for inline markers.
+uint32_t HELPER(get_fpsr)(CPUM68KState *env)
+{
+ int host_flags = get_float_exception_flags(&env->fp_status);
+ int target_flags = cpu_m68k_exceptbits_from_host(host_flags);
+ int except = (env->fpsr & ~(0xf8)) | target_flags;
+ return except;
+}
+
+uint32_t cpu_m68k_get_fpsr(CPUM68KState *env)
+{
+ return HELPER(get_fpsr)(env);
+}
In general it is bad form to call HELPER(foo) directly.
In this case it doesn't hurt, but better form to reverse the implementations.
+void HELPER(set_fpsr)(CPUM68KState *env, uint32_t val)
+{
+ env->fpsr = val;
+
+ int host_flags = cpu_m68k_exceptbits_to_host((int) env->fpsr);
+ set_float_exception_flags(host_flags, &env->fp_status);
+}
+
+void cpu_m68k_set_fpsr(CPUM68KState *env, uint32_t val)
+{
+ return HELPER(set_fpsr)(env, val);
+}
Likewise.
What's missing is an update to vmstate, to make sure all the architectural bits are
properly saved. Add
env->fpsr = cpu_m68k_get_fpsr(env);
to a (new) fpu_pre_save and
cpu_m68k_set_fpsr(env, env->fpsr);
to fpu_post_load in target/m68k/cpu.c.
r~
