diff --git a/src/x86.h b/src/x86.h
new file mode 100644
index 0000000..8550f0c
--- /dev/null
+++ b/src/x86.h
@@ -0,0 +1,35 @@
+#pragma once
+
+// Can expression be expressed as a single x86 operand?
+#define XOP_NOT_XOP 0
+#define XOP_NOT_MEM 1
+#define XOP_MEM 2
+static inline int is_xop(AST *e) {
+	if(e->nodeKind == AST_EXPR_PRIMITIVE) {
+		return XOP_NOT_MEM;
+	} else if(e->nodeKind == AST_EXPR_VAR) {
+		return e->exprVar.thing->kind == VARTABLEENTRY_VAR ? XOP_NOT_MEM : XOP_MEM;
+	} else if(e->nodeKind == AST_EXPR_UNARY_OP && e->exprUnOp.operator == UNOP_DEREF && e->exprUnOp.operand->nodeKind == AST_EXPR_BINARY_OP && e->exprUnOp.operand->exprBinOp.operator == BINOP_ADD && e->exprUnOp.operand->exprBinOp.operands[0]->nodeKind == AST_EXPR_VAR && e->exprUnOp.operand->exprBinOp.operands[1]->nodeKind == AST_EXPR_VAR && e->exprUnOp.operand->exprBinOp.operands[0]->exprVar.thing->kind == VARTABLEENTRY_VAR && e->exprUnOp.operand->exprBinOp.operands[1]->exprVar.thing->kind == VARTABLEENTRY_VAR) {
+		return XOP_MEM;
+	} else if(e->nodeKind == AST_EXPR_UNARY_OP && e->exprUnOp.operator == UNOP_REF && e->exprUnOp.operand->nodeKind == AST_EXPR_VAR && e->exprUnOp.operand->exprVar.thing->kind == VARTABLEENTRY_SYMBOL) {
+		return XOP_NOT_MEM;
+	} else if(e->nodeKind == AST_EXPR_UNARY_OP && e->exprUnOp.operator == UNOP_DEREF) {
+		AST *c = e->exprUnOp.operand;
+		
+		if(c->nodeKind == AST_EXPR_VAR && c->exprVar.thing->kind == VARTABLEENTRY_VAR) {
+			return XOP_MEM;
+		} else if(c->nodeKind == AST_EXPR_BINARY_OP && c->exprBinOp.operator == BINOP_ADD && c->exprBinOp.operands[0]->nodeKind == AST_EXPR_UNARY_OP && c->exprBinOp.operands[0]->exprUnOp.operator == UNOP_REF && c->exprBinOp.operands[0]->exprUnOp.operand->nodeKind == AST_EXPR_VAR) {
+			if(c->exprBinOp.operands[1]->nodeKind == AST_EXPR_VAR) {
+				return XOP_MEM;
+			} else if(c->exprBinOp.operands[1]->nodeKind == AST_EXPR_BINARY_OP && c->exprBinOp.operands[1]->exprBinOp.operator == BINOP_MUL && c->exprBinOp.operands[1]->exprBinOp.operands[0]->nodeKind == AST_EXPR_PRIMITIVE && c->exprBinOp.operands[1]->exprBinOp.operands[1]->nodeKind == AST_EXPR_VAR) {
+				int scale = c->exprBinOp.operands[1]->exprBinOp.operands[0]->exprPrim.val;
+				
+				if(scale == 1 || scale == 2 || scale == 4 || scale == 8) {
+					return XOP_MEM;
+				}
+			}
+		}
+	}
+	
+	return XOP_NOT_XOP;
+}