target/m68k: Implement TRAPcc

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/754
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220602013401.303699-11-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

linux-user/m68k/cpu_loop.c

@@ -47,6 +47,7 @@ void cpu_loop(CPUM68KState *env)
             force_sig_fault(TARGET_SIGILL, TARGET_ILL_ILLOPN, env->pc);
             break;
         case EXCP_CHK:
+        case EXCP_TRAPCC:
             force_sig_fault(TARGET_SIGFPE, TARGET_FPE_INTOVF, env->mmu.ar);
             break;
         case EXCP_DIV0:

target/m68k/cpu.c

@@ -158,6 +158,7 @@ static void m68020_cpu_initfn(Object *obj)
     m68k_set_feature(env, M68K_FEATURE_CHK2);
     m68k_set_feature(env, M68K_FEATURE_MSP);
     m68k_set_feature(env, M68K_FEATURE_UNALIGNED_DATA);
+    m68k_set_feature(env, M68K_FEATURE_TRAPCC);
 }
 
 /*

target/m68k/cpu.h

@@ -534,6 +534,8 @@ enum m68k_features {
     M68K_FEATURE_MOVEC,
     /* Unaligned data accesses (680[2346]0) */
     M68K_FEATURE_UNALIGNED_DATA,
+    /* TRAPcc insn. (680[2346]0, and CPU32) */
+    M68K_FEATURE_TRAPCC,
 };
 
 static inline int m68k_feature(CPUM68KState *env, int feature)

target/m68k/op_helper.c

@@ -399,14 +399,10 @@ static void m68k_interrupt_all(CPUM68KState *env, int is_hw)
         do_stack_frame(env, &sp, 2, oldsr, 0, env->pc);
         break;
 
-    case EXCP_TRAPCC:
-        /* FIXME: addr is not only env->pc */
-        do_stack_frame(env, &sp, 2, oldsr, env->pc, env->pc);
-        break;
-
     case EXCP_CHK:
     case EXCP_DIV0:
     case EXCP_TRACE:
+    case EXCP_TRAPCC:
         do_stack_frame(env, &sp, 2, oldsr, env->mmu.ar, env->pc);
         break;
 

target/m68k/translate.c

@@ -4879,6 +4879,53 @@ DISAS_INSN(trap)
     gen_exception(s, s->pc, EXCP_TRAP0 + (insn & 0xf));
 }
 
+static void do_trapcc(DisasContext *s, DisasCompare *c)
+{
+    if (c->tcond != TCG_COND_NEVER) {
+        TCGLabel *over = NULL;
+
+        update_cc_op(s);
+
+        if (c->tcond != TCG_COND_ALWAYS) {
+            /* Jump over if !c. */
+            over = gen_new_label();
+            tcg_gen_brcond_i32(tcg_invert_cond(c->tcond), c->v1, c->v2, over);
+        }
+
+        tcg_gen_movi_i32(QREG_PC, s->pc);
+        gen_raise_exception_format2(s, EXCP_TRAPCC, s->base.pc_next);
+
+        if (over != NULL) {
+            gen_set_label(over);
+            s->base.is_jmp = DISAS_NEXT;
+        }
+    }
+    free_cond(c);
+}
+
+DISAS_INSN(trapcc)
+{
+    DisasCompare c;
+
+    /* Consume and discard the immediate operand. */
+    switch (extract32(insn, 0, 3)) {
+    case 2: /* trapcc.w */
+        (void)read_im16(env, s);
+        break;
+    case 3: /* trapcc.l */
+        (void)read_im32(env, s);
+        break;
+    case 4: /* trapcc (no operand) */
+        break;
+    default:
+        /* trapcc registered with only valid opmodes */
+        g_assert_not_reached();
+    }
+
+    gen_cc_cond(&c, s, extract32(insn, 8, 4));
+    do_trapcc(s, &c);
+}
+
 static void gen_load_fcr(DisasContext *s, TCGv res, int reg)
 {
     switch (reg) {
@@ -6051,6 +6098,8 @@ void register_m68k_insns (CPUM68KState *env)
     INSN(scc,       50c0, f0f8, CF_ISA_A); /* Scc.B Dx   */
     INSN(scc,       50c0, f0c0, M68000);   /* Scc.B <EA> */
     INSN(dbcc,      50c8, f0f8, M68000);
+    INSN(trapcc,    50fa, f0fe, TRAPCC);   /* opmode 010, 011 */
+    INSN(trapcc,    50fc, f0ff, TRAPCC);   /* opmode 100 */
     INSN(tpf,       51f8, fff8, CF_ISA_A);
 
     /* Branch instructions.  */