target-m68k: add cas/cas2 ops

Implement CAS using cmpxchg.
Implement CAS2 using helper and either cmpxchg when
the 32bit addresses are consecutive, or with
parallel_cpus+cpu_loop_exit_atomic() otherwise.

Suggested-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>

1 files changed, 109 insertions, 0 deletions

diff --git a/target/m68k/op_helper.c b/target/m68k/op_helper.c
index 04246a92b4..e56b815d73 100644
--- a/target/m68k/op_helper.c
+++ b/target/m68k/op_helper.c
@@ -360,3 +360,112 @@ void HELPER(divsll)(CPUM68KState *env, int numr, int regr, int32_t den)
     env->dregs[regr] = rem;
     env->dregs[numr] = quot;
 }
+
+void HELPER(cas2w)(CPUM68KState *env, uint32_t regs, uint32_t a1, uint32_t a2)
+{
+    uint32_t Dc1 = extract32(regs, 9, 3);
+    uint32_t Dc2 = extract32(regs, 6, 3);
+    uint32_t Du1 = extract32(regs, 3, 3);
+    uint32_t Du2 = extract32(regs, 0, 3);
+    int16_t c1 = env->dregs[Dc1];
+    int16_t c2 = env->dregs[Dc2];
+    int16_t u1 = env->dregs[Du1];
+    int16_t u2 = env->dregs[Du2];
+    int16_t l1, l2;
+    uintptr_t ra = GETPC();
+
+    if (parallel_cpus) {
+        /* Tell the main loop we need to serialize this insn.  */
+        cpu_loop_exit_atomic(ENV_GET_CPU(env), ra);
+    } else {
+        /* We're executing in a serial context -- no need to be atomic.  */
+        l1 = cpu_lduw_data_ra(env, a1, ra);
+        l2 = cpu_lduw_data_ra(env, a2, ra);
+        if (l1 == c1 && l2 == c2) {
+            cpu_stw_data_ra(env, a1, u1, ra);
+            cpu_stw_data_ra(env, a2, u2, ra);
+        }
+    }
+
+    if (c1 != l1) {
+        env->cc_n = l1;
+        env->cc_v = c1;
+    } else {
+        env->cc_n = l2;
+        env->cc_v = c2;
+    }
+    env->cc_op = CC_OP_CMPW;
+    env->dregs[Dc1] = deposit32(env->dregs[Dc1], 0, 16, l1);
+    env->dregs[Dc2] = deposit32(env->dregs[Dc2], 0, 16, l2);
+}
+
+void HELPER(cas2l)(CPUM68KState *env, uint32_t regs, uint32_t a1, uint32_t a2)
+{
+    uint32_t Dc1 = extract32(regs, 9, 3);
+    uint32_t Dc2 = extract32(regs, 6, 3);
+    uint32_t Du1 = extract32(regs, 3, 3);
+    uint32_t Du2 = extract32(regs, 0, 3);
+    uint32_t c1 = env->dregs[Dc1];
+    uint32_t c2 = env->dregs[Dc2];
+    uint32_t u1 = env->dregs[Du1];
+    uint32_t u2 = env->dregs[Du2];
+    uint32_t l1, l2;
+    uintptr_t ra = GETPC();
+#if defined(CONFIG_ATOMIC64) && !defined(CONFIG_USER_ONLY)
+    int mmu_idx = cpu_mmu_index(env, 0);
+    TCGMemOpIdx oi;
+#endif
+
+    if (parallel_cpus) {
+        /* We're executing in a parallel context -- must be atomic.  */
+#ifdef CONFIG_ATOMIC64
+        uint64_t c, u, l;
+        if ((a1 & 7) == 0 && a2 == a1 + 4) {
+            c = deposit64(c2, 32, 32, c1);
+            u = deposit64(u2, 32, 32, u1);
+#ifdef CONFIG_USER_ONLY
+            l = helper_atomic_cmpxchgq_be(env, a1, c, u);
+#else
+            oi = make_memop_idx(MO_BEQ, mmu_idx);
+            l = helper_atomic_cmpxchgq_be_mmu(env, a1, c, u, oi, ra);
+#endif
+            l1 = l >> 32;
+            l2 = l;
+        } else if ((a2 & 7) == 0 && a1 == a2 + 4) {
+            c = deposit64(c1, 32, 32, c2);
+            u = deposit64(u1, 32, 32, u2);
+#ifdef CONFIG_USER_ONLY
+            l = helper_atomic_cmpxchgq_be(env, a2, c, u);
+#else
+            oi = make_memop_idx(MO_BEQ, mmu_idx);
+            l = helper_atomic_cmpxchgq_be_mmu(env, a2, c, u, oi, ra);
+#endif
+            l2 = l >> 32;
+            l1 = l;
+        } else
+#endif
+        {
+            /* Tell the main loop we need to serialize this insn.  */
+            cpu_loop_exit_atomic(ENV_GET_CPU(env), ra);
+        }
+    } else {
+        /* We're executing in a serial context -- no need to be atomic.  */
+        l1 = cpu_ldl_data_ra(env, a1, ra);
+        l2 = cpu_ldl_data_ra(env, a2, ra);
+        if (l1 == c1 && l2 == c2) {
+            cpu_stl_data_ra(env, a1, u1, ra);
+            cpu_stl_data_ra(env, a2, u2, ra);
+        }
+    }
+
+    if (c1 != l1) {
+        env->cc_n = l1;
+        env->cc_v = c1;
+    } else {
+        env->cc_n = l2;
+        env->cc_v = c2;
+    }
+    env->cc_op = CC_OP_CMPL;
+    env->dregs[Dc1] = l1;
+    env->dregs[Dc2] = l2;
+}