target-xtensa: Use clz opcode

Signed-off-by: Richard Henderson <rth@twiddle.net>
qemu · Jan 10, 2017 · b79ea94 · b79ea94
1 parent 03a733d
commit b79ea94
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Showing 3 changed files with 11 additions and 17 deletions.
diff --git a/target/xtensa/helper.h b/target/xtensa/helper.h
@@ -3,8 +3,6 @@ DEF_HELPER_3(exception_cause, noreturn, env, i32, i32)
 DEF_HELPER_4(exception_cause_vaddr, noreturn, env, i32, i32, i32)
 DEF_HELPER_3(debug_exception, noreturn, env, i32, i32)
 
-DEF_HELPER_FLAGS_1(nsa, TCG_CALL_NO_RWG_SE, i32, i32)
-DEF_HELPER_FLAGS_1(nsau, TCG_CALL_NO_RWG_SE, i32, i32)
 DEF_HELPER_2(wsr_windowbase, void, env, i32)
 DEF_HELPER_4(entry, void, env, i32, i32, i32)
 DEF_HELPER_2(retw, i32, env, i32)

diff --git a/target/xtensa/op_helper.c b/target/xtensa/op_helper.c
@@ -161,19 +161,6 @@ void HELPER(debug_exception)(CPUXtensaState *env, uint32_t pc, uint32_t cause)
     HELPER(exception)(env, EXC_DEBUG);
 }
 
-uint32_t HELPER(nsa)(uint32_t v)
-{
-    if (v & 0x80000000) {
-        v = ~v;
-    }
-    return v ? clz32(v) - 1 : 31;
-}
-
-uint32_t HELPER(nsau)(uint32_t v)
-{
-    return v ? clz32(v) : 32;
-}
-
 static void copy_window_from_phys(CPUXtensaState *env,
         uint32_t window, uint32_t phys, uint32_t n)
 {

diff --git a/target/xtensa/translate.c b/target/xtensa/translate.c
@@ -1372,14 +1372,23 @@ static void disas_xtensa_insn(CPUXtensaState *env, DisasContext *dc)
                 case 14: /*NSAu*/
                     HAS_OPTION(XTENSA_OPTION_MISC_OP_NSA);
                     if (gen_window_check2(dc, RRR_S, RRR_T)) {
-                        gen_helper_nsa(cpu_R[RRR_T], cpu_R[RRR_S]);
+                        TCGv_i32 t0 = tcg_temp_new_i32();
+
+                        /* if (v & 0x80000000) v = ~v; */
+                        tcg_gen_sari_i32(t0, cpu_R[RRR_S], 31);
+                        tcg_gen_xor_i32(t0, t0, cpu_R[RRR_S]);
+
+                        /* r = (v ? clz(v) : 32) - 1; */
+                        tcg_gen_clzi_i32(t0, t0, 32);
+                        tcg_gen_subi_i32(cpu_R[RRR_T], t0, 1);
+                        tcg_temp_free_i32(t0);
                     }
                     break;
 
                 case 15: /*NSAUu*/
                     HAS_OPTION(XTENSA_OPTION_MISC_OP_NSA);
                     if (gen_window_check2(dc, RRR_S, RRR_T)) {
-                        gen_helper_nsau(cpu_R[RRR_T], cpu_R[RRR_S]);
+                        tcg_gen_clzi_i32(cpu_R[RRR_T], cpu_R[RRR_S], 32);
                     }
                     break;