diff mbox series

[v4,03/24] target/m68k: Keep FPSR up-to-date

Message ID 20250224171444.440135-4-richard.henderson@linaro.org
State New
Headers show
Series target/m68k: fpu improvements | expand

Commit Message

Richard Henderson Feb. 24, 2025, 5:14 p.m. UTC
Proper support for m68k exceptions will require testing the FPCR vs
the FPSR for every instruction.  As a step, do not keep FPSR bits in
fp_status, but copy them back to the FPSR in every instruction.

Since most of the FPSR must be updated on every insn, handle this
from the existing helper_ftst and helper_fcmp functions.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/m68k/cpu.h        |  2 -
 target/m68k/helper.h     |  2 -
 target/m68k/cpu.c        | 10 -----
 target/m68k/fpu_helper.c | 94 +++++++++++-----------------------------
 target/m68k/helper.c     |  4 +-
 target/m68k/translate.c  |  4 +-
 6 files changed, 30 insertions(+), 86 deletions(-)
diff mbox series

Patch

diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h
index e26d416bf4..7b90e1e58f 100644
--- a/target/m68k/cpu.h
+++ b/target/m68k/cpu.h
@@ -201,8 +201,6 @@  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 95aa5e53bb..2bbe0dc032 100644
--- a/target/m68k/helper.h
+++ b/target/m68k/helper.h
@@ -54,8 +54,6 @@  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 76f8dfca2b..5dbad8bb43 100644
--- a/target/m68k/cpu.c
+++ b/target/m68k/cpu.c
@@ -410,20 +410,11 @@  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_set_fpcr(&s->env, s->env.fpcr);
-    cpu_m68k_set_fpsr(&s->env, s->env.fpsr);
     return 0;
 }
 
@@ -432,7 +423,6 @@  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 a6d93ff325..d5551bee41 100644
--- a/target/m68k/fpu_helper.c
+++ b/target/m68k/fpu_helper.c
@@ -164,76 +164,34 @@  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)
+static void update_fpsr(CPUM68KState *env, int cc)
 {
-    int target_bits = 0;
+    uint32_t fpsr = env->fpsr;
+    int flags = get_float_exception_flags(&env->fp_status);
 
-    if (host_bits & float_flag_invalid) {
-        target_bits |= FPSR_AEXP_IOP;
-    }
-    if (host_bits & float_flag_overflow) {
-        target_bits |= FPSR_AEXP_OVFL;
-    }
-    if (host_bits & (float_flag_underflow | float_flag_output_denormal_flushed)) {
-        target_bits |= FPSR_AEXP_UNFL;
-    }
-    if (host_bits & float_flag_divbyzero) {
-        target_bits |= FPSR_AEXP_DZ;
-    }
-    if (host_bits & float_flag_inexact) {
-        target_bits |= FPSR_AEXC_INEX;
-    }
-    return target_bits;
-}
+    fpsr &= ~FPSR_CC_MASK;
+    fpsr |= cc;
 
-/* Convert cpu_m68k exception flags to target form.  */
-static int cpu_m68k_exceptbits_to_host(int target_bits)
-{
-    int host_bits = 0;
+    if (flags) {
+        set_float_exception_flags(0, &env->fp_status);
 
-    if (target_bits & FPSR_AEXP_IOP) {
-        host_bits |= float_flag_invalid;
+        if (flags & float_flag_invalid) {
+            fpsr |= FPSR_AEXP_IOP;
+        }
+        if (flags & float_flag_overflow) {
+            fpsr |= FPSR_AEXP_OVFL;
+        }
+        if (flags & (float_flag_underflow | float_flag_output_denormal_flushed)) {
+            fpsr |= FPSR_AEXP_UNFL;
+        }
+        if (flags & float_flag_divbyzero) {
+            fpsr |= FPSR_AEXP_DZ;
+        }
+        if (flags & float_flag_inexact) {
+            fpsr |= FPSR_AEXC_INEX;
+        }
     }
-    if (target_bits & FPSR_AEXP_OVFL) {
-        host_bits |= float_flag_overflow;
-    }
-    if (target_bits & FPSR_AEXP_UNFL) {
-        host_bits |= float_flag_underflow;
-    }
-    if (target_bits & FPSR_AEXP_DZ) {
-        host_bits |= float_flag_divbyzero;
-    }
-    if (target_bits & FPSR_AEXC_INEX) {
-        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 & ~FPSR_AEXC_MASK) | 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);
+    env->fpsr = fpsr;
 }
 
 #define PREC_BEGIN(prec)                                        \
@@ -442,12 +400,12 @@  void HELPER(fcmp)(CPUM68KState *env, FPReg *val0, FPReg *val1)
     FloatRelation float_compare;
 
     float_compare = floatx80_compare(val1->d, val0->d, &env->fp_status);
-    env->fpsr = (env->fpsr & ~FPSR_CC_MASK) | float_comp_to_cc(float_compare);
+    update_fpsr(env, float_comp_to_cc(float_compare));
 }
 
 void HELPER(ftst)(CPUM68KState *env, FPReg *val)
 {
-    uint32_t cc = 0;
+    int cc = 0;
 
     if (floatx80_is_neg(val->d)) {
         cc |= FPSR_CC_N;
@@ -460,7 +418,7 @@  void HELPER(ftst)(CPUM68KState *env, FPReg *val)
     } else if (floatx80_is_zero(val->d)) {
         cc |= FPSR_CC_Z;
     }
-    env->fpsr = (env->fpsr & ~FPSR_CC_MASK) | cc;
+    update_fpsr(env, cc);
 }
 
 void HELPER(fconst)(CPUM68KState *env, FPReg *val, uint32_t offset)
diff --git a/target/m68k/helper.c b/target/m68k/helper.c
index beefeb7069..6e3bb96762 100644
--- a/target/m68k/helper.c
+++ b/target/m68k/helper.c
@@ -90,7 +90,7 @@  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, cpu_m68k_get_fpsr(env));
+        return gdb_get_reg32(mem_buf, env->fpsr);
     case 10: /* fpiar, not implemented */
         return gdb_get_reg32(mem_buf, 0);
     }
@@ -112,7 +112,7 @@  static int m68k_fpu_gdb_set_reg(CPUState *cs, uint8_t *mem_buf, int n)
         cpu_m68k_set_fpcr(env, ldl_be_p(mem_buf));
         return 4;
     case 9: /* fpstatus */
-        cpu_m68k_set_fpsr(env, ldl_be_p(mem_buf));
+        env->fpsr = ldl_be_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 dec2967fce..d3cfad315c 100644
--- a/target/m68k/translate.c
+++ b/target/m68k/translate.c
@@ -4733,7 +4733,7 @@  static void gen_load_fcr(DisasContext *s, TCGv res, int reg)
         tcg_gen_movi_i32(res, 0);
         break;
     case M68K_FPSR:
-        gen_helper_get_fpsr(res, tcg_env);
+        tcg_gen_ld_i32(res, tcg_env, offsetof(CPUM68KState, fpsr));
         break;
     case M68K_FPCR:
         tcg_gen_ld_i32(res, tcg_env, offsetof(CPUM68KState, fpcr));
@@ -4747,7 +4747,7 @@  static void gen_store_fcr(DisasContext *s, TCGv val, int reg)
     case M68K_FPIAR:
         break;
     case M68K_FPSR:
-        gen_helper_set_fpsr(tcg_env, val);
+        tcg_gen_st_i32(val, tcg_env, offsetof(CPUM68KState, fpsr));
         break;
     case M68K_FPCR:
         gen_helper_set_fpcr(tcg_env, val);