Add CLEAR_BYTE() macro

nfurfaro · Oct 15, 2023 · 8be928b · 8be928b
1 parent a14349d
commit 8be928b
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Showing 3 changed files with 30 additions and 7 deletions.
diff --git a/src/Huffbits.huff b/src/Huffbits.huff
@@ -17,6 +17,7 @@
 #define function writeNibble(uint256, uint256, uint256) pure returns(uint256)
 #define function clearNibble(uint256, uint256) pure returns(uint256)
 #define function queryNibble(uint256, uint256) pure returns(uint256)
+#define function clearByte(uint256, uint256) pure returns(uint256)
 
 #define constant MAX = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
 
@@ -172,4 +173,11 @@
     0x04               //            [4, index, and]
     mul                //                [prod, and]
     shr                //                  [shifted]
+}
+
+/// Given a bitmap, clear a nibble if set, otherwise return the original bitmap.
+#define macro CLEAR_BYTE() = takes(2) returns(1) {
+    // input stack     //          [index, bitmap]
+    BYTEMASK()       //             [mask, bitmap]
+    and
 }
diff --git a/test/Huffbits.t.sol b/test/Huffbits.t.sol
@@ -17,6 +17,7 @@ interface Huffbits {
     function writeNibble(uint256, uint256, uint256) external pure returns(uint256);
     function clearNibble(uint256, uint256) external pure returns(uint256);
     function queryNibble(uint256, uint256) external pure returns(uint256);
+    function clearByte(uint256, uint256) external pure returns(uint256);
 }
 
 
@@ -151,7 +152,10 @@ contract HuffbitsTest is Test {
         assertEq(huffbits.byteMask(31), 0x00FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF);
     }
 
-    // byteMask
+    function testClearByte() public {
+        assertEq(huffbits.clearByte(1, 0), 0);
+    }
+
     // clearByte
     // WriteByte
     // queryByte

diff --git a/test/mocks/HuffbitsWrappers.huff b/test/mocks/HuffbitsWrappers.huff
@@ -69,17 +69,25 @@
 }
 
 #define macro CLEAR_NIBBLE_WRAPPER() = {
-    0x04 calldataload  //         [arg1]
-    0x24 calldataload  //   [arg2, arg1]
-    CLEAR_NIBBLE()        //   [cleared]
+    0x04 calldataload   //        [arg1]
+    0x24 calldataload   //   arg2, arg1]
+    CLEAR_NIBBLE()      //     [cleared]
     0x00 mstore
     0x20 0x00 return
 }
 
 #define macro QUERY_NIBBLE_WRAPPER() = {
-    0x04 calldataload  //         [arg1]
-    0x24 calldataload  //   [arg2, arg1]
-    QUERY_NIBBLE()        //   [result]
+    0x04 calldataload   //        [arg1]
+    0x24 calldataload   //  [arg2, arg1]
+    QUERY_NIBBLE()      //      [result]
+    0x00 mstore
+    0x20 0x00 return
+}
+
+#define macro CLEAR_BYTE_WRAPPER() = {
+    0x04 calldataload   //      [arg1]
+    0x24 calldataload   //[arg2, arg1]
+    CLEAR_BYTE()        //   [cleared]
     0x00 mstore
     0x20 0x00 return
 }
@@ -97,6 +105,7 @@
     dup1 __FUNC_SIG(writeNibble) eq writeNibble jumpi
     dup1 __FUNC_SIG(clearNibble) eq clearNibble jumpi
     dup1 __FUNC_SIG(queryNibble) eq queryNibble jumpi
+    dup1 __FUNC_SIG(clearByte) eq clearByte jumpi
 
 
     0x00 0x00 revert
@@ -123,4 +132,6 @@
         CLEAR_NIBBLE_WRAPPER()
     queryNibble:
         QUERY_NIBBLE_WRAPPER()
+    clearByte:
+        CLEAR_BYTE_WRAPPER()
 }