style: modernize to splitseq, cut, min, maps.copy and range-over-int

asm/arm64_assemble.go

@@ -638,7 +638,7 @@ func encodeARM64LoadImm(rd int, v int64, mnem string) ([]byte, error) {
 	// Multi-instruction: MOVZ + MOVK for each non-zero16-bit chunk.
 	var ws []uint32
 	first := true
-	for i := 0; i < 4; i++ {
+	for i := range 4 {
 		chunk := (d >> uint(i*16)) & 0xFFFF
 		if chunk == 0 {
 			continue
@@ -679,7 +679,7 @@ func arm64Bitmask(v uint64, sf int) (N, immr, imms uint32, ok bool) {
 		}
 
 		// Check each rotation: is the rotated pattern a contiguous block of 1s at the LSB?
-		for r := uint(0); r < esize; r++ {
+		for r := range esize {
 			rotated := (pattern >> r) | ((pattern << (esize - r)) & emask)
 			if rotated == 0 {
 				continue