README

Utilities for emulating WebAssembly 32-bit and 64-bit integer operations in PHP. These may be useful for porting an application or library from C, C++, or other languages.

Requirements

This package requires a 64-bit build of PHP 8.4 or later.

There is no dependency on external Composer packages or PHP extensions.

Installation

Install via Composer.

composer require adept-digital/int-utils

Usage

There are two classes with near-identical interfaces:

• \AdeptDigital\IntUtils\Int32
• \AdeptDigital\IntUtils\Int64

The following operations are provided:

• add(int $a, int $b): int: Integer addition.
• sub(int $a, int $b): int: Integer subtraction.
• mul(int $a, int $b): int: Integer multiplication.
• div_s(int $a, int $b): int: Signed integer division. ¹
• div_u(int $a, int $b): int: Unsigned integer division.
• rem_s(int $a, int $b): int: Signed integer modulo. ¹
• rem_u(int $a, int $b): int: Unsigned integer modulo.
• eq(int $a, int $b): int: Equal comparison. ²
• eqz(int $a): int: Equals zero test. ²
• ne(int $a, int $b): int: Not equal comparison. ²
• lt_s(int $a, int $b): int: Signed less than comparison. ²
• lt_u(int $a, int $b): int: Unsigned less than comparison.
• le_s(int $a, int $b): int: Signed less than or equal comparison. ²
• le_u(int $a, int $b): int: Unsigned less than or equal comparison.
• gt_s(int $a, int $b): int: Signed greater than comparison. ²
• gt_u(int $a, int $b): int: Unsigned greater than comparison.
• ge_s(int $a, int $b): int: Signed greater than or equal comparison. ²
• ge_u(int $a, int $b): int: Unsigned greater than or equal comparison.
• and(int $a, int $b): int: Bitwise AND. ¹
• or(int $a, int $b): int: Bitwise OR. ¹
• xor(int $a, int $b): int: Bitwise XOR. ¹
• shl(int $a, int $b): int: Shift left. ²
• shr_s(int $a, int $b): int: Signed (arithmetic) shift right. ²
• shr_u(int $a, int $b): int: Unsigned (logical) shift right.
• rotl(int $a, int $b): int: Rotate left.
• rotr(int $a, int $b): int: Rotate right.
• clz(int $a): int: Count leading zeros.
• ctz(int $a): int: Count trailing zeros.
• popcnt(int $a): int: Population count.
• extend8_s(int $a): int: Extend the sign of the least significant 8 bits.
• extend16_s(int $a): int: Extend the sign of the least significant 16 bits.
• extend32_s(int $a): int: Extend the sign of the least significant 32 bits. ³

32-bit representation

PHP has no 32-bit integer type, so 32-bit numbers are represented in 64-bit, but are limited to the range of a signed 32-bit integer (-2,147,483,648 to 2,147,483,647). For example, 4,294,967,295 (2**32-1) should be represented as -1. Using numbers outside this range will cause a RangeException to be thrown, unless assertions are disabled, in which case the result is undefined.

To correctly format an unsigned 32-bit integer, unset the most significant 32 bits:

use \AdeptDigital\IntUtils\Int32;

echo Int32::add(Int32::MAX, 1) & 0xFFFF_FFFF;
// output: 2147483648

64-bit representation

PHP has no unsigned integer type, so numbers larger than PHP_INT_MAX will appear to be negative.

To correctly format an unsigned integer, use printf() or sprintf():

use \AdeptDigital\IntUtils\Int64;

printf('%u', Int64::add(Int64::MAX, 1));
// output: 9223372036854775808

Contributing

All contributions are welcome. If you would like to work on a new feature, consider creating an issue before starting.

TODO

• Add benchmarks and benchmark on different machines.
• Add alternative implementations (eg: GMP, FFI, custom extension).
• Add feature detection for alternative implementations.

License

Copyright 2025 David Gallagher david@adeptdigital.com.au.

The package is licensed under the GNU Lesser General Public License 3.0 or later.

Footnotes

1. Method is only provided for completeness. It does nothing different when compared to the equivalent PHP operator. ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Method only provides a trivial transformation on inputs or output. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

3. Only available on the \AdeptDigital\IntUtils\Int64 class. ↩