feat(asm): byte-identical go-flac AVX2 assembly with scalar families and jump relaxation

Assisted-by: Qwen 3.8 Max Preview

parser/parser.go

@@ -400,22 +400,29 @@ func parseAddress(g []token.Token) ast.Address {
 	}
 
 	i := 0
-	// Optional leading displacement before a '(' base group.
-	if isSignedNumber(g, i) && i+1 < len(g) && g[i+1].Kind == token.LParen {
-		neg := false
-		if g[i].Kind == token.Minus {
-			neg = true
-			i++
-		} else if g[i].Kind == token.Plus {
-			i++
+	// Optional leading displacement before a '(' base group.  A sign pushes
+	// the parenthesis one token further out: -4(DX) has it at i+2.
+	if isSignedNumber(g, i) {
+		paren := i + 1
+		if g[i].Kind == token.Minus || g[i].Kind == token.Plus {
+			paren = i + 2
 		}
-		if i < len(g) && g[i].Kind == token.Number {
-			addr.Offset = parseInt(g[i].Text)
-			addr.HasOff = true
-			if neg {
-				addr.Offset = -addr.Offset
+		if paren < len(g) && g[paren].Kind == token.LParen {
+			neg := false
+			if g[i].Kind == token.Minus {
+				neg = true
+				i++
+			} else if g[i].Kind == token.Plus {
+				i++
+			}
+			if i < len(g) && g[i].Kind == token.Number {
+				addr.Offset = parseInt(g[i].Text)
+				addr.HasOff = true
+				if neg {
+					addr.Offset = -addr.Offset
+				}
+				i++
 			}
-			i++
 		}
 	}
 	// First parenthesised group: the base register.