Created
December 31, 2022 01:33
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| //////////// uint | |
| uint8(x) , x £ [0, 255] = [0x00, 0xff] = [0, 2^8 - 1] | |
| uint16(x) , x £ [0, 65535] = [0, 2^16 - 1] | |
| uint24(x) , x £ [0, 16777215] = [0, 2^24 - 1] | |
| uint32(x) | |
| uint40(x) | |
| ... | |
| uint256(x) , x £ [0, 2^256 - 1] | |
| //////////// int | |
| int8(x) , x £ [-128, 127] = [-2**(8-1) , 2**(8-1)-1] | |
| //////////// bytes | |
| uint8(x) = bytes1(x) , x £ [0x00, 0xff] | |
| uint16(x) = bytes2(x) , x £ [0x0000, 0xffff] | |
| hex"Ff" = 0xff | |
| bytes1(x) , x £ [0x00, 0xff] | |
| bytes2(x) , x £ [0x0000, 0xffff] | |
| bytes3(x) , x £ [0x000000, 0xffffff] | |
| ... | |
| bytes32(x) | |
| bytes != bytes1 (sol v < v0.8.0 , bytes == bytes1) | |
| 0xff_ff is int_const | |
| hex"ff_ff" is bytes | |
| ///// bytes shift (NO overflow error) | |
| » bytes2(hex"ffff") << 1 | |
| 0xfffe | |
| » bytes2(hex"ffff") << 2 | |
| 0xfffc | |
| » bytes2(hex"ffff") << 8 | |
| 0xff00 | |
| » bytes2(hex"ffff") << 16 | |
| 0x0000 | |
| » bytes2(hex"ffff") >> 16 | |
| 0x0000 | |
| » bytes2(hex"ffff") >> 8 | |
| 0x00ff | |
| ////// | |
| » bytes2(0x1122) | |
| 0x1122 | |
| » bytes2(0x1122)[0] | |
| 0x11 | |
| » bytes2(0x1122)[1] | |
| 0x22 | |
| » bytes2(a[0]) >> 8 | bytes2(a[1]) | |
| 0x2211 | |
| » bytes3 b = bytes3(0x112233) | |
| 0x112233 | |
| » bytes3(b[0]) >> 16 | bytes3(b[1]) >> 8 | bytes3(b[2]) | |
| 0x332211 | |
| » bytes3(b[1]) | |
| 0x220000 | |
| » b.length | |
| 3 | |
| //// int bytes shift | |
| 9 << 2 = 36 , x * 2**y | |
| 9 >> 2 = 2 , x / 2**y | |
| -3 << 1 = -6 | |
| -5 >> 1 = -3 (E(-2.5)) | |
| //////// bitwise negation (be careful) | |
| ~int256(0) == int256(-1) | |
| » ~0x01 | |
| -2 | |
| » // 0000 0001 => 1000 0010 !! | |
| » ~0x00 | |
| -1 | |
| » // 0000 0000 => 1000 0001 !! | |
| ///////////// Two's Complement | |
| // representing -1 | |
| 0000 0001 | |
| 1. invert the digits | |
| 1111 1110 | |
| 2. add 1 | |
| 1111 1111 | |
| // get -1 from binary representation | |
| invert digits | |
| 0000 0000 | |
| add 1 | |
| 0000 0001 |
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