SHL Shift Left MASM Operator expression SHL count Shifts expression left by count bits. Notes: Bits shifted off the end are lost. Zeroes are entered when shifting. If count is greater than or equal to 16, the result is 0. If the value being shifted is a word, all 16-bits will be shifted. However, if the value is only a byte, only 8-bits will be shifted. Seealso: