A specific mnemonic within a range is referred to by mnemonic and number. A15 is
bit 15 of accumulator A; ADDR7 is line 7 of the address bus; CSOR0 is chip-select op-
tion register 0. A range of mnemonics is referred to by mnemonic and the numbers
that define the range. AM[35:30] are bits 35 to 30 of accumulator M; CSOR[0:5] are
the first six option registers.
Parentheses are used to indicate the content of a register or memory location, rather
than the register or memory location itself. (A) is the content of accumulator A. (M : M
+ 1) is the content of the word at address M.
LSB means least significant bit or bits. MSB means most significant bit or bits. Refer-
ences to low and high bytes are spelled out.
LSW means least significant word or words. MSW means most significant word or
words.
ADDR is the address bus. ADDR[7:0] are the eight LSB of the address bus.
DATA is the data bus. DATA[15:8] are the eight MSB of the data bus.
2
MC68331
NOMENCLATURE
MOTOROLA
2-7
USER’S MANUAL
MOTOROLA [ MOTOROLA ]
