From: Keith Packard <keithp@keithp.com>
Add helpers for reading/writing the 68881 FPSR register so that
changes in floating point exception state can be seen by the
application.
Call these helpers in pre_load/post_load hooks to synchronize
exception state.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230803035231.429697-1-keithp@keithp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
target/m68k/cpu.h | 3 +-
target/m68k/helper.h | 2 ++
target/m68k/cpu.c | 12 +++++--
target/m68k/fpu_helper.c | 72 ++++++++++++++++++++++++++++++++++++++++
target/m68k/helper.c | 4 +--
target/m68k/translate.c | 4 +--
6 files changed, 90 insertions(+), 7 deletions(-)
diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h
index 346427e144..e184239a81 100644
--- a/target/m68k/cpu.h
+++ b/target/m68k/cpu.h
@@ -199,7 +199,8 @@ void cpu_m68k_set_ccr(CPUM68KState *env, uint32_t);
void cpu_m68k_set_sr(CPUM68KState *env, uint32_t);
void cpu_m68k_restore_fp_status(CPUM68KState *env);
void cpu_m68k_set_fpcr(CPUM68KState *env, uint32_t val);
-
+uint32_t cpu_m68k_get_fpsr(CPUM68KState *env);
+void cpu_m68k_set_fpsr(CPUM68KState *env, uint32_t val);
/*
* Instead of computing the condition codes after each m68k instruction,
diff --git a/target/m68k/helper.h b/target/m68k/helper.h
index 2bbe0dc032..95aa5e53bb 100644
--- a/target/m68k/helper.h
+++ b/target/m68k/helper.h
@@ -54,6 +54,8 @@ DEF_HELPER_4(fsdiv, void, env, fp, fp, fp)
DEF_HELPER_4(fddiv, void, env, fp, fp, fp)
DEF_HELPER_4(fsgldiv, void, env, fp, fp, fp)
DEF_HELPER_FLAGS_3(fcmp, TCG_CALL_NO_RWG, void, env, fp, fp)
+DEF_HELPER_2(set_fpsr, void, env, i32)
+DEF_HELPER_1(get_fpsr, i32, env)
DEF_HELPER_FLAGS_2(set_fpcr, TCG_CALL_NO_RWG, void, env, i32)
DEF_HELPER_FLAGS_2(ftst, TCG_CALL_NO_RWG, void, env, fp)
DEF_HELPER_3(fconst, void, env, fp, i32)
diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
index 7c8efbb42c..df49ff1880 100644
--- a/target/m68k/cpu.c
+++ b/target/m68k/cpu.c
@@ -390,12 +390,19 @@ static const VMStateDescription vmstate_freg = {
}
};
+static int fpu_pre_save(void *opaque)
+{
+ M68kCPU *s = opaque;
+
+ s->env.fpsr = cpu_m68k_get_fpsr(&s->env);
+ return 0;
+}
+
static int fpu_post_load(void *opaque, int version)
{
M68kCPU *s = opaque;
- cpu_m68k_restore_fp_status(&s->env);
-
+ cpu_m68k_set_fpsr(&s->env, s->env.fpsr);
return 0;
}
@@ -404,6 +411,7 @@ const VMStateDescription vmmstate_fpu = {
.version_id = 1,
.minimum_version_id = 1,
.needed = fpu_needed,
+ .pre_save = fpu_pre_save,
.post_load = fpu_post_load,
.fields = (const VMStateField[]) {
VMSTATE_UINT32(env.fpcr, M68kCPU),
diff --git a/target/m68k/fpu_helper.c b/target/m68k/fpu_helper.c
index ab120b5f59..8314791f50 100644
--- a/target/m68k/fpu_helper.c
+++ b/target/m68k/fpu_helper.c
@@ -164,6 +164,78 @@ void HELPER(set_fpcr)(CPUM68KState *env, uint32_t val)
cpu_m68k_set_fpcr(env, val);
}
+/* Convert host exception flags to cpu_m68k form. */
+static int cpu_m68k_exceptbits_from_host(int host_bits)
+{
+ int target_bits = 0;
+
+ if (host_bits & float_flag_invalid) {
+ target_bits |= 0x80;
+ }
+ if (host_bits & float_flag_overflow) {
+ target_bits |= 0x40;
+ }
+ if (host_bits & (float_flag_underflow | float_flag_output_denormal)) {
+ target_bits |= 0x20;
+ }
+ if (host_bits & float_flag_divbyzero) {
+ target_bits |= 0x10;
+ }
+ if (host_bits & float_flag_inexact) {
+ target_bits |= 0x08;
+ }
+ return target_bits;
+}
+
+/* Convert cpu_m68k exception flags to target form. */
+static int cpu_m68k_exceptbits_to_host(int target_bits)
+{
+ int host_bits = 0;
+
+ if (target_bits & 0x80) {
+ host_bits |= float_flag_invalid;
+ }
+ if (target_bits & 0x40) {
+ host_bits |= float_flag_overflow;
+ }
+ if (target_bits & 0x20) {
+ host_bits |= float_flag_underflow;
+ }
+ if (target_bits & 0x10) {
+ host_bits |= float_flag_divbyzero;
+ }
+ if (target_bits & 0x08) {
+ host_bits |= float_flag_inexact;
+ }
+ return host_bits;
+}
+
+uint32_t cpu_m68k_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 HELPER(get_fpsr)(CPUM68KState *env)
+{
+ return cpu_m68k_get_fpsr(env);
+}
+
+void cpu_m68k_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 HELPER(set_fpsr)(CPUM68KState *env, uint32_t val)
+{
+ cpu_m68k_set_fpsr(env, val);
+}
+
#define PREC_BEGIN(prec) \
do { \
FloatX80RoundPrec old = \
diff --git a/target/m68k/helper.c b/target/m68k/helper.c
index 1a475f082a..7a91f33b17 100644
--- a/target/m68k/helper.c
+++ b/target/m68k/helper.c
@@ -87,7 +87,7 @@ static int m68k_fpu_gdb_get_reg(CPUState *cs, GByteArray *mem_buf, int n)
case 8: /* fpcontrol */
return gdb_get_reg32(mem_buf, env->fpcr);
case 9: /* fpstatus */
- return gdb_get_reg32(mem_buf, env->fpsr);
+ return gdb_get_reg32(mem_buf, cpu_m68k_get_fpsr(env));
case 10: /* fpiar, not implemented */
return gdb_get_reg32(mem_buf, 0);
}
@@ -109,7 +109,7 @@ static int m68k_fpu_gdb_set_reg(CPUState *cs, uint8_t *mem_buf, int n)
cpu_m68k_set_fpcr(env, ldl_p(mem_buf));
return 4;
case 9: /* fpstatus */
- env->fpsr = ldl_p(mem_buf);
+ cpu_m68k_set_fpsr(env, ldl_p(mem_buf));
return 4;
case 10: /* fpiar, not implemented */
return 4;
diff --git a/target/m68k/translate.c b/target/m68k/translate.c
index 6ae3df43bc..8a194f2f21 100644
--- a/target/m68k/translate.c
+++ b/target/m68k/translate.c
@@ -4686,7 +4686,7 @@ static void gen_load_fcr(DisasContext *s, TCGv res, int reg)
tcg_gen_movi_i32(res, 0);
break;
case M68K_FPSR:
- tcg_gen_ld_i32(res, tcg_env, offsetof(CPUM68KState, fpsr));
+ gen_helper_get_fpsr(res, tcg_env);
break;
case M68K_FPCR:
tcg_gen_ld_i32(res, tcg_env, offsetof(CPUM68KState, fpcr));
@@ -4700,7 +4700,7 @@ static void gen_store_fcr(DisasContext *s, TCGv val, int reg)
case M68K_FPIAR:
break;
case M68K_FPSR:
- tcg_gen_st_i32(val, tcg_env, offsetof(CPUM68KState, fpsr));
+ gen_helper_set_fpsr(tcg_env, val);
break;
case M68K_FPCR:
gen_helper_set_fpcr(tcg_env, val);
--
2.34.1