Adding modding folder with a hacked build.

modding/hacked/ss1/content/numbers/BinaryCodedDecimal.go

@@ -0,0 +1,26 @@
+package numbers
+
+// ToBinaryCodedDecimal converts given integer value to a 4-digit BCD value.
+func ToBinaryCodedDecimal(value uint16) (bcd uint16) {
+	factors := []uint16{1000, 100, 10, 1}
+	value %= 10000
+
+	for _, factor := range factors {
+		bcd = (bcd << 4) | (value / factor)
+		value %= factor
+	}
+
+	return
+}
+
+// FromBinaryCodedDecimal converts given 4-digit BCD value into an integer.
+func FromBinaryCodedDecimal(bcd uint16) (value uint16) {
+	factors := []uint16{1, 10, 100, 1000}
+
+	for _, factor := range factors {
+		value += (bcd & 0xF) * factor
+		bcd >>= 4
+	}
+
+	return
+}

modding/hacked/ss1/content/numbers/BinaryCodedDecimal_test.go

@@ -0,0 +1,37 @@
+package numbers_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/inkyblackness/hacked/ss1/content/numbers"
+)
+
+func TestBinaryCodedDecimal(t *testing.T) {
+	tt := []struct {
+		int uint16
+		bcd uint16
+	}{
+		{int: 0, bcd: 0x0000},
+		{int: 1, bcd: 0x0001},
+		{int: 20, bcd: 0x0020},
+		{int: 300, bcd: 0x0300},
+		{int: 4000, bcd: 0x4000},
+		{int: 50000, bcd: 0x0000},
+		{int: 9999, bcd: 0x9999},
+		{int: 451, bcd: 0x0451},
+	}
+
+	for _, tc := range tt {
+		toBCD := numbers.ToBinaryCodedDecimal(tc.int)
+		assert.Equal(t, tc.bcd, toBCD, "Wrong result converting to BCD for %d", tc.int)
+
+		fromBCD := numbers.FromBinaryCodedDecimal(tc.bcd)
+		if tc.int <= 9999 {
+			assert.Equal(t, tc.int, fromBCD, "Wrong result converting from BCD for %d", tc.int)
+		} else {
+			assert.Equal(t, uint16(0), fromBCD, "Wrong result converting from BCD for %d", tc.int)
+		}
+	}
+}