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Implement Big UInt Bitwise Or for modexp #135

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merged 6 commits into from
Sep 27, 2023
Merged

Implement Big UInt Bitwise Or for modexp #135

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edd8528
Implement bigUIntBitOr
jpcenteno Sep 25, 2023
b684970
Fix bigUIntBitOr
jpcenteno Sep 26, 2023
95c7a5f
Merge branch 'modexp_reimplementation' into 132-implement-big-uint-bi…
jpcenteno Sep 26, 2023
ae9aae0
Fix bigUIntBitOr
jpcenteno Sep 26, 2023
6fa84eb
Fix missing closing brackets
jpcenteno Sep 26, 2023
4507e0a
Merge branch 'modexp_reimplementation' into 132-implement-big-uint-bi…
jpcenteno Sep 26, 2023
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33 changes: 32 additions & 1 deletion precompiles/Modexp.yul
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Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,37 @@ object "ModExp" {
}
}

/// @notice Performs the big unsigned integer bit or operation.
/// @dev The result is stored from `resPtr` to `resPtr + (LIMB_SIZE * nLimbs)`.
/// @param lhsPtr The pointer to the MSB of the left operand.
/// @param rhsPtr The pointer to the MSB of the right operand.
/// @param nLimbs The number of limbs needed to represent the operands.
/// @param resPtr The pointer to where you want the result to be stored
function bigUIntBitOr(lhsPtr, rhsPtr, nLimbs, resPtr) {
// +------------+-----------------------+-------------------------------+-------------------------------+-------------------------------+-----------------+-----------------+--------------------------------------+
// | Iteration | offset_i | ptr_lhs_i | ptr_rhs_i | ptr_res_i | value_lhs_i | value_rhs_i | value_res_i |
// +------------+-----------------------+-------------------------------+-------------------------------+-------------------------------+-----------------+-----------------+--------------------------------------+
// | 0 | +0x00 | lhsPtr + 0x00 | rhsPtr + 0x00 | resPtr + 0x00 | lhs[0] | rhs[0] | or(lhs[0], rhs[0]) |
// | 1 | +0x20 | lhsPtr + 0x20 | rhsPtr + 0x20 | resPtr + 0x20 | lhs[1] | rhs[1] | or(lhs[1], rhs[1]) |
// | 2 | +0x40 | lhsPtr + 0x40 | rhsPtr + 0x40 | resPtr + 0x40 | lhs[2] | rhs[2] | or(lhs[2], rhs[2]) |
// | | | | | | | | |
// | ... | ... | ... | ... | ... | ... | ... | ... |
// | | | | | | | | |
// | nLimbs - 1 | +(0x20 * (nLimbs - 1) | lhsPtr + (0x20 * (nLimbs - 1) | rhsPtr + (0x20 * (nLimbs - 1) | resPtr + (0x20 * (nLimbs - 1) | lhs[nLimbs - 1] | rhs[nLimbs - 1] | or(lhs[nLimbs - 1], rhs[nLimbs - 1]) |
// +------------+-----------------------+-------------------------------+-------------------------------+-------------------------------+-----------------+-----------------+--------------------------------------+

let finalOffset := shl(5, nLimbs) // == ( LIMB_SIZE * nLimbs ) == (32 * nLimbs)
for { let offset_i := 0 } lt(offset_i, finalOffset) { offset_i := add(offset_i, 0x20) }
{
let ptr_lhs_i := add(lhsPtr, offset_i)
let ptr_lhs_i := add(rhsPtr, offset_i)
let ptr_res_i := add(resPtr, offset_i)
let value_lhs_i := mload(ptr_lhs_i)
let value_rhs_i := mload(ptr_lhs_i)
let value_res_i := or(value_lhs_i, value_rhs_i)
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mstore(ptr_res_i, value_res_i)
}

////////////////////////////////////////////////////////////////
// FALLBACK
////////////////////////////////////////////////////////////////
Expand Down Expand Up @@ -126,4 +157,4 @@ object "ModExp" {
// TODO: big arithmetics
}
}
}
}