avoid extra check from compiler during math ops

Signed-off-by: Uncle Fatso <uncle.fatso@ghostchain.io>

src/libraries/FullMath.sol

@@ -3,17 +3,20 @@ pragma solidity ^0.8.20;
 
 library FullMath {
     function fullMul(uint256 x, uint256 y) private pure returns (uint256 l, uint256 h) {
+        unchecked {
             uint256 mm = mulmod(x, y, type(uint256).max);
             l = x * y;
             h = mm - l;
             if (mm < l) h -= 1;
         }
+    }
 
     function fullDiv(
         uint256 l,
         uint256 h,
         uint256 d
     ) private pure returns (uint256) {
+        unchecked {
             uint256 pow2 = d & (~d + 1);
             d /= pow2;
             l /= pow2;
@@ -29,15 +32,19 @@ library FullMath {
             r *= 2 - d * r;
             return l * r;
         }
+    }
 
     function mulDiv(
         uint256 x,
         uint256 y,
         uint256 d
     ) internal pure returns (uint256) {
-        (uint256 l, uint256 h) = fullMul(x, y);
+        if (d == 0) revert("FullMath: DIVISION_BY_ZERO");
 
+        unchecked {
+            (uint256 l, uint256 h) = fullMul(x, y);
             uint256 mm = mulmod(x, y, d);
+
             if (mm > l) h -= 1;
             l -= mm;
 
@@ -47,3 +54,4 @@ library FullMath {
             return fullDiv(l, h, d);
         }
     }
+}