chore: replace unnecessarily complex sign extension implementation

src/util.zig

@@ -1,29 +1,8 @@
 const std = @import("std");
 
-pub fn u32SignExtend(comptime bits: usize, value: u32) u32 {
-    return @bitCast(u32, signExtend(i32, bits, @bitCast(i32, value)));
-}
-
-fn signExtend(comptime T: type, comptime bits: usize, value: anytype) T {
-    const ValT = comptime @TypeOf(value);
-    comptime std.debug.assert(isInteger(ValT));
-    comptime std.debug.assert(isSigned(ValT));
-
-    const value_bits = @typeInfo(ValT).Int.bits;
-    comptime std.debug.assert(value_bits >= bits);
-
-    const bit_diff = value_bits - bits;
-
-    // (1 << bits) -1 is a mask that will take values like 0x100 and make them 0xFF
-    // value & mask so that only the relevant bits are sign extended
-    // therefore, value & ((1 << bits) - 1) is the isolation of the relevant bits
-    return ((value & ((1 << bits) - 1)) << bit_diff) >> bit_diff;
-}
-
-fn isInteger(comptime T: type) bool {
-    return @typeInfo(T) == .Int;
-}
-
-fn isSigned(comptime T: type) bool {
-    return @typeInfo(T).Int.signedness == .signed;
+pub fn sext(comptime bits: comptime_int, value: u32) u32 {
+    comptime std.debug.assert(bits <= 32);
+    const amount = 32 - bits;
+
+    return @bitCast(u32, @bitCast(i32, value << amount) >> amount);
 }