1 files changed, 193 insertions, 0 deletions
diff --git a/src/WebAssembly/Execution/NumericOps.php b/src/WebAssembly/Execution/NumericOps.php
new file mode 100644
index 0000000..895b8c2
--- /dev/null
+++ b/src/WebAssembly/Execution/NumericOps.php
@@ -0,0 +1,193 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Nsfisis\Waddiwasi\WebAssembly\Execution;
+
+use InvalidArgumentException;
+use function assert;
+use function bcadd;
+use function bccomp;
+use function bcmod;
+use function bcpow;
+use function bcsub;
+use function fdiv;
+use function is_nan;
+use function pack;
+use function unpack;
+
+final readonly class NumericOps
+{
+    private function __construct()
+    {
+    }
+
+    public static function reinterpretI32AsF32(int $x): float
+    {
+        return self::deserializeF32FromBytes(self::serializeI32ToBytes($x));
+    }
+
+    public static function reinterpretI64AsF32(int $x): float
+    {
+        return self::deserializeF32FromBytes(self::serializeI64ToBytes($x));
+    }
+
+    public static function reinterpretI32AsF64(int $x): float
+    {
+        return self::deserializeF64FromBytes(self::serializeI32ToBytes($x));
+    }
+
+    public static function reinterpretI64AsF64(int $x): float
+    {
+        return self::deserializeF64FromBytes(self::serializeI64ToBytes($x));
+    }
+
+    public static function reinterpretF32AsI32(float $x): int
+    {
+        return self::deserializeI32FromBytes(self::serializeF32ToBytes($x));
+    }
+
+    public static function reinterpretF64AsI32(float $x): int
+    {
+        return self::deserializeI32FromBytes(self::serializeF64ToBytes($x));
+    }
+
+    public static function reinterpretF32AsI64(float $x): int
+    {
+        return self::deserializeI64FromBytes(self::serializeF32ToBytes($x));
+    }
+
+    public static function reinterpretF64AsI64(float $x): int
+    {
+        return self::deserializeI64FromBytes(self::serializeF64ToBytes($x));
+    }
+
+    public static function truncateF64ToF32(float $x): float
+    {
+        return self::deserializeF32FromBytes(self::serializeF32ToBytes($x));
+    }
+
+    public static function serializeI32ToBytes(int $x): string
+    {
+        return pack('l', $x);
+    }
+
+    public static function deserializeI32FromBytes(string $s): int
+    {
+        $result = unpack('l', $s);
+        if ($result === false) {
+            throw new InvalidArgumentException("Failed to unpack i32: $s");
+        }
+        return $result[1];
+    }
+
+    public static function serializeI64ToBytes(int $x): string
+    {
+        return pack('q', $x);
+    }
+
+    public static function deserializeI64FromBytes(string $s): int
+    {
+        $result = unpack('q', $s);
+        if ($result === false) {
+            throw new InvalidArgumentException("Failed to unpack i64: $s");
+        }
+        return $result[1];
+    }
+
+    public static function serializeF32ToBytes(float $x): string
+    {
+        return pack('f', $x);
+    }
+
+    public static function deserializeF32FromBytes(string $s): float
+    {
+        $result = unpack('f', $s);
+        if ($result === false) {
+            throw new InvalidArgumentException("Failed to unpack f32: $s");
+        }
+        return $result[1];
+    }
+
+    public static function serializeF64ToBytes(float $x): string
+    {
+        return pack('d', $x);
+    }
+
+    public static function deserializeF64FromBytes(string $s): float
+    {
+        $result = unpack('d', $s);
+        if ($result === false) {
+            throw new InvalidArgumentException("Failed to unpack f64: $s");
+        }
+        return $result[1];
+    }
+
+    public static function convertS32ToU32(int $x): int
+    {
+        // assert(-0x80000000 <= $x && $x <= 0x7FFFFFFF, "convertS32ToU32: out of range $x");
+        if ($x < 0) {
+            $buf = pack('l', $x);
+            $result = unpack('L', $buf);
+            assert($result !== false);
+            assert(0x00000000 <= $result[1] && $result[1] <= 0xFFFFFFFF, "convertS32ToU32: out of range $result[1]");
+            return $result[1];
+        } else {
+            return $x;
+        }
+    }
+
+    public static function convertU32ToS32(int $x): int
+    {
+        assert(0x00000000 <= $x && $x <= 0xFFFFFFFF);
+        if (($x & 0x80000000) !== 0) {
+            $buf = pack('L', $x);
+            $result = unpack('l', $buf);
+            assert($result !== false);
+            assert(-0x80000000 <= $result[1] && $result[1] <= 0x7FFFFFFF, "convertU32ToS32: out of range $result[1]");
+            return $result[1];
+        } else {
+            return $x;
+        }
+    }
+
+    public static function convertS64ToBigUInt(int $x): string
+    {
+        if ($x < 0) {
+            return bcadd((string)$x, '18446744073709551616');
+        } else {
+            return (string)$x;
+        }
+    }
+
+    public static function bigIntToPhpInt(string $s): int
+    {
+        $result = bcmod($s, bcpow('2', '64'));
+        if ($result[0] === '-') {
+            // 2^63 <= -$result
+            if (bccomp(bcpow('2', '63'), bcsub('0', $result)) <= 0) {
+                $result = bcadd($result, bcpow('2', '64'));
+            }
+        } else {
+            // 2^63-1 < $result
+            if (bccomp(bcsub(bcpow('2', '63'), '1'), $result) < 0) {
+                $result = bcsub($result, bcpow('2', '64'));
+            }
+        }
+        return (int)$result;
+    }
+
+    public static function getFloatSign(float $p): int
+    {
+        if (is_nan($p)) {
+            $n = self::reinterpretF64AsI64($p);
+            // The MSB is the sign bit.
+            return (($n >> 63) & 1) === 1 ? -1 : 1;
+        } elseif ($p !== 0.0) {
+            return $p < 0.0 ? -1 : 1;
+        } else {
+            // Comparison with 0 does not work for -0.0.
+            return fdiv(1, $p) < 0.0 ? -1 : 1;
+        }
+    }
+}