[PATCH 28/45] target/hppa: Introduce DisasDelayException

[Richard Henderson]

Allow an exception to be emitted at the end of the TranslationBlock,
leaving only the conditional branch inline.  Use it for simple
exception instructions like break, which happen to be nullified.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/hppa/translate.c | 60 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 5 deletions(-)

diff --git a/target/hppa/translate.c b/target/hppa/translate.c
index 5714e2ad25..7a92901e18 100644
--- a/target/hppa/translate.c
+++ b/target/hppa/translate.c
@@ -50,6 +50,17 @@ typedef struct DisasIAQE {
     int64_t disp;
 } DisasIAQE;
 
+typedef struct DisasDelayException {
+    struct DisasDelayException *next;
+    TCGLabel *lab;
+    uint32_t insn;
+    bool set_iir;
+    int8_t set_n;
+    uint8_t excp;
+    /* Saved state at parent insn. */
+    DisasIAQE iaq_f, iaq_b;
+} DisasDelayException;
+
 typedef struct DisasContext {
     DisasContextBase base;
     CPUState *cs;
@@ -65,6 +76,7 @@ typedef struct DisasContext {
     DisasCond null_cond;
     TCGLabel *null_lab;
 
+    DisasDelayException *delay_excp_list;
     TCGv_i64 zero;
 
     uint32_t insn;
@@ -682,13 +694,38 @@ static void gen_excp(DisasContext *ctx, int exception)
     ctx->base.is_jmp = DISAS_NORETURN;
 }
 
+static DisasDelayException *delay_excp(DisasContext *ctx, uint8_t excp)
+{
+    DisasDelayException *e = tcg_malloc(sizeof(DisasDelayException));
+
+    memset(e, 0, sizeof(*e));
+    e->next = ctx->delay_excp_list;
+    ctx->delay_excp_list = e;
+
+    e->lab = gen_new_label();
+    e->insn = ctx->insn;
+    e->set_iir = true;
+    e->set_n = ctx->psw_n_nonzero ? 0 : -1;
+    e->excp = excp;
+    e->iaq_f = ctx->iaq_f;
+    e->iaq_b = ctx->iaq_b;
+
+    return e;
+}
+
 static bool gen_excp_iir(DisasContext *ctx, int exc)
 {
-    nullify_over(ctx);
-    tcg_gen_st_i64(tcg_constant_i64(ctx->insn),
-                   tcg_env, offsetof(CPUHPPAState, cr[CR_IIR]));
-    gen_excp(ctx, exc);
-    return nullify_end(ctx);
+    if (ctx->null_cond.c == TCG_COND_NEVER) {
+        tcg_gen_st_i64(tcg_constant_i64(ctx->insn),
+                       tcg_env, offsetof(CPUHPPAState, cr[CR_IIR]));
+        gen_excp(ctx, exc);
+    } else {
+        DisasDelayException *e = delay_excp(ctx, exc);
+        tcg_gen_brcond_i64(tcg_invert_cond(ctx->null_cond.c),
+                           ctx->null_cond.a0, ctx->null_cond.a1, e->lab);
+        ctx->null_cond = cond_make_f();
+    }
+    return true;
 }
 
 static bool gen_illegal(DisasContext *ctx)
@@ -4695,6 +4732,19 @@ static void hppa_tr_tb_stop(DisasContextBase *dcbase, 
CPUState *cs)
     default:
         g_assert_not_reached();
     }
+
+    for (DisasDelayException *e = ctx->delay_excp_list; e ; e = e->next) {
+        gen_set_label(e->lab);
+        if (e->set_n >= 0) {
+            tcg_gen_movi_i64(cpu_psw_n, e->set_n);
+        }
+        if (e->set_iir) {
+            tcg_gen_st_i64(tcg_constant_i64(e->insn), tcg_env,
+                           offsetof(CPUHPPAState, cr[CR_IIR]));
+        }
+        install_iaq_entries(ctx, &e->iaq_f, &e->iaq_b);
+        gen_excp_1(e->excp);
+    }
 }
 
 static void hppa_tr_disas_log(const DisasContextBase *dcbase,
-- 
2.34.1