Daily Archives: August 4, 2020

one’s & two’s complement number system

在計算機的底層是用0、1來表示資料,因此人類的符號系統要透過電腦表示就需要做編碼轉換,ASCII、Unicode等都是做此用途,而在(整數)數字系統的編碼,比較常見的有 ASCII (將數字用ASCII表示) -200 => 2D 32 30 30 BCD 189 => 01 08 09 (packed BCD) one’s complement (assume 8-bit size) 0 => 0000 0000b -0 => 1111 1111b (unsigned = 255) -1=> 1111 1110b (unsigned = 254) 127 … Continue reading

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