update decimal128 mul_u128

initia-labs · Sep 4, 2024 · 9c54ba2 · 9c54ba2
1 parent 6623a5c
commit 9c54ba2
Showing 1 changed file with 15 additions and 8 deletions.
diff --git a/precompile/modules/initia_stdlib/sources/decimal128.move b/precompile/modules/initia_stdlib/sources/decimal128.move
@@ -105,24 +105,31 @@ module initia_std::decimal128 {
         (val / (DECIMAL_FRACTIONAL as u256) as u64)
     }
 
+    fun mul_u128_with_extra(decimal: &Decimal128, val: u128, extra: u128): u128 {
+        let a_quota = (decimal.val / DECIMAL_FRACTIONAL as u256);
+        let a_remainder = (decimal.val % DECIMAL_FRACTIONAL as u256);
+
+        let b_quota = (val / DECIMAL_FRACTIONAL as u256);
+        let b_remainder = (val % DECIMAL_FRACTIONAL as u256);
+
+        ((a_quota * b_quota * (DECIMAL_FRACTIONAL as u256) + 
+            a_quota * b_remainder + b_quota * a_remainder + (a_remainder * b_remainder + (extra as u256)) / (DECIMAL_FRACTIONAL as u256)) as u128)
+    }
+
     public fun mul_u128(decimal: &Decimal128, val: u128): u128 {
-        ((decimal.val as u256) * (val as u256) / (DECIMAL_FRACTIONAL as u256) as u128)
+        mul_u128_with_extra(decimal, val, 0)
     }
 
     public fun mul_u128_with_round_up(decimal: &Decimal128, val: u128): u128 {
-        let val = (decimal.val as u256) * (val as u256);
-        let val = val + (DECIMAL_FRACTIONAL as u256) / 2;
-        (val / (DECIMAL_FRACTIONAL as u256) as u128)
+        mul_u128_with_extra(decimal, val, DECIMAL_FRACTIONAL / 2)
     }
 
     public fun mul_u128_with_ceil(decimal: &Decimal128, val: u128): u128 {
-        let val = (decimal.val as u256) * (val as u256);
-        let val = val + (DECIMAL_FRACTIONAL as u256) - 1;
-        (val / (DECIMAL_FRACTIONAL as u256) as u128)
+        mul_u128_with_extra(decimal, val, DECIMAL_FRACTIONAL - 1)
     }
 
     public fun mul(a: &Decimal128, b: &Decimal128): Decimal128 {
-        new(((a.val as u256) * (b.val as u256) / (DECIMAL_FRACTIONAL as u256) as u128))
+        new(mul_u128(a, b.val))
     }
 
     public fun div_u64(decimal: &Decimal128, val: u64): Decimal128 {