Messing with flags. subficx sometimes still wrong.

src/alloy/backend/x64/lowering/lowering_sequences.cc

@@ -113,13 +113,6 @@ uint64_t LoadClock(void* raw_context) {
   return time;
 }
 
-void CallNative(X64Emitter& e, void* target) {
-  e.mov(e.rax, (uint64_t)target);
-  e.call(e.rax);
-  e.mov(e.rcx, e.qword[e.rsp + 0]);
-  e.mov(e.rdx, e.qword[e.rcx + 8]); // membase
-}
-
 // TODO(benvanik): fancy stuff.
 void* ResolveFunctionSymbol(void* raw_context, FunctionInfo* symbol_info) {
   // TODO(benvanik): generate this thunk at runtime? or a shim?
@@ -1161,6 +1154,8 @@ table->AddSequence(OPCODE_STORE, [](X64Emitter& e, Instr*& i) {
         // eh?
         e.bswap(e.r8);
         CallNative(e, cbs->write);
+        i = e.Advance(i);
+        return true;
       }
       cbs = cbs->next;
     }
@@ -1534,6 +1529,7 @@ table->AddSequence(OPCODE_COMPARE_UGE, [](X64Emitter& e, Instr*& i) {
 table->AddSequence(OPCODE_DID_CARRY, [](X64Emitter& e, Instr*& i) {
   Reg8 dest;
   e.BeginOp(i->dest, dest, REG_DEST);
+  LoadEflags(e);
   e.setc(dest);
   e.EndOp(dest);
   i = e.Advance(i);
@@ -1543,6 +1539,7 @@ table->AddSequence(OPCODE_DID_CARRY, [](X64Emitter& e, Instr*& i) {
 table->AddSequence(OPCODE_DID_OVERFLOW, [](X64Emitter& e, Instr*& i) {
   Reg8 dest;
   e.BeginOp(i->dest, dest, REG_DEST);
+  LoadEflags(e);
   e.seto(dest);
   e.EndOp(dest);
   i = e.Advance(i);

src/alloy/backend/x64/lowering/op_utils.inl

@@ -17,6 +17,30 @@ namespace {
 #define LIKE_REG(dest, like) Reg(dest.getIdx(), dest.getKind(), like.getBit(), false)
 #define NAX_LIKE(like) Reg(e.rax.getIdx(), e.rax.getKind(), like.getBit(), false)
 
+// If we are running with tracing on we have to store the EFLAGS in the stack,
+// otherwise our calls out to C to print will clear it before DID_CARRY/etc
+// can get the value.
+#define STORE_EFLAGS 1
+
+void LoadEflags(X64Emitter& e) {
+#if STORE_EFLAGS
+  e.mov(e.eax, e.dword[e.rsp + 40]);
+  e.push(e.ax);
+  e.popf();
+#else
+  // EFLAGS already present.
+#endif  // STORE_EFLAGS
+}
+void StoreEflags(X64Emitter& e) {
+#if STORE_EFLAGS
+  e.pushf();
+  e.pop(e.word[e.rsp + 40]);
+#else
+  // EFLAGS should have CA set?
+  // (so long as we don't fuck with it)
+#endif  // STORE_EFLAGS
+}
+
 Address Stash(X64Emitter& e, const Xmm& r) {
   // TODO(benvanik): ensure aligned.
   auto addr = e.ptr[e.rsp + 48];
@@ -39,6 +63,15 @@ void MovMem64(X64Emitter& e, RegExp& addr, uint64_t v) {
   }
 }
 
+void CallNative(X64Emitter& e, void* target) {
+  e.sub(e.rsp, 0x18);
+  e.mov(e.rax, (uint64_t)target);
+  e.call(e.rax);
+  e.mov(e.rcx, e.qword[e.rsp + 0]);
+  e.mov(e.rdx, e.qword[e.rcx + 8]); // membase
+  e.add(e.rsp, 0x18);
+}
+
 // Sets EFLAGs with zf for the given value.
 // ZF = 1 if false, 0 = true (so jz = jump if false)
 void CheckBoolean(X64Emitter& e, Value* v) {
@@ -421,9 +454,7 @@ void IntUnaryOp(X64Emitter& e, Instr*& i, v_fn v_fn) {
     ASSERT_INVALID_TYPE();
   }
   if (i->flags & ARITHMETIC_SET_CARRY) {
-    // EFLAGS should have CA set?
+    StoreEflags(e);
-    // (so long as we don't fuck with it)
-    // UNIMPLEMENTED_SEQ();
   }
 };
 
@@ -598,9 +629,7 @@ void IntBinaryOp(X64Emitter& e, Instr*& i, vv_fn vv_fn, vc_fn vc_fn) {
     ASSERT_INVALID_TYPE();
   }
   if (i->flags & ARITHMETIC_SET_CARRY) {
-    // EFLAGS should have CA set?
+    StoreEflags(e);
-    // (so long as we don't fuck with it)
-    // UNIMPLEMENTED_SEQ();
   }
 };
 
@@ -777,9 +806,7 @@ void IntTernaryOp(X64Emitter& e, Instr*& i, vvv_fn vvv_fn, vvc_fn vvc_fn, vcv_fn
     ASSERT_INVALID_TYPE();
   }
   if (i->flags & ARITHMETIC_SET_CARRY) {
-    // EFLAGS should have CA set?
+    StoreEflags(e);
-    // (so long as we don't fuck with it)
-    // UNIMPLEMENTED_SEQ();
   }
 }
 
@@ -946,9 +973,7 @@ void XmmBinaryOp(X64Emitter& e, Instr*& i, uint32_t flags, xmm_vv_fn vv_fn) {
     ASSERT_INVALID_TYPE();
   }
   if (flags & ARITHMETIC_SET_CARRY) {
-    // EFLAGS should have CA set?
+    StoreEflags(e);
-    // (so long as we don't fuck with it)
-    // UNIMPLEMENTED_SEQ();
   }
 };
 
@@ -992,9 +1017,7 @@ void XmmTernaryOp(X64Emitter& e, Instr*& i, uint32_t flags, xmm_vvv_fn vvv_fn) {
     ASSERT_INVALID_TYPE();
   }
   if (flags & ARITHMETIC_SET_CARRY) {
-    // EFLAGS should have CA set?
+    StoreEflags(e);
-    // (so long as we don't fuck with it)
-    // UNIMPLEMENTED_SEQ();
   }
 };