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The integer data that are directly supported by the computer hardware have a fixed width of a low power of 2, e.g. 8 bits ≙ 1 byte, 16 bits ≙ 2 bytes, 32 bits ≙ 4 bytes, 64 bits ≙ 8 bytes, 128 bits ≙ 16 bytes. The low-level access sequence to the bytes of such a field depends on the operation to be performed.
Break the number up into groups of 7 bits. Output one encoded byte for each 7 bit group, from least significant to most significant group. Each byte will have the group in its 7 least significant bits. Set the most significant bit on each byte except the last byte. The number zero is usually encoded as a single byte 0x00.
The format of data on the tape is: 100 bytes with the value 0x16 (SYN, Synchronous Idle), one byte with the value 0x2A (*), the record identification number, the start address (two characters for the low byte of address, two characters for the high byte), the end address (in the same format), the actual data, one byte with the value 0x2F ...
The actual number of bits of precision can vary. In general, the magnitude of the low-order part of the number is no greater than half ULP of the high-order part. If the low-order part is less than half ULP of the high-order part, significant bits (either all 0s or all 1s) are implied between the significant of the high-order and low-order numbers.
In modern textbooks one kilobyte is defined as 1,000 byte, one megabyte as 1,000,000 byte, etc., in accordance with the 1998 International Electrotechnical Commission (IEC) standard. However, the convention adopted by Windows systems is to define 1 kilobyte is as 1,024 (or 2 10 ) bytes, which is equal to 1 kibibyte .
Each sequence begins with a one-byte token that is broken into two 4-bit fields. The first field represents the number of literal bytes that are to be copied to the output. The second field represents the number of bytes to copy from the already decoded output buffer (with 0 representing the minimum match length of 4 bytes).
The high-order byte of the instruction specifies the operation. Bits 9 through 15 are the op-code, and bit 8 is the value of the condition code calculation which results in the branch being taken. The low-order byte is a signed word offset relative to the current location of the program counter. This allows for forward and reverse branches in code.
The 68000 has a 24-bit external address bus and two byte-select signals "replaced" A0. These 24 lines can therefore address 16 MB of physical memory with byte resolution. Address storage and computation uses 32 bits internally; however, the 8 high-order address bits are ignored due to the physical lack of device pins.