4.2 Instruction Set
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4.2 Instruction Set
Table 4.2.1 Explanation of Items in Table of Instructions
Item
Explanation
Mnemonic
Upper-case letters and symbols: ........ Described as they appear in assembler.
Lower-case letters: ............................. Replaced when described in assembler.
Numbers after lower-case letters: ...... Indicate the bit width within the instruction.
#
Indicates the number of bytes.
~
Indicates the number of cycles.
See Table 4.2.4 for details about meanings of letters in items.
RG
Indicates the register access count during execution of instruction.
Used to calculate compensation values for CPU intermittent operation.
B
Indicates the compensation value for calculating the number of actual cycles during execution
of instruction.
The number of actual cycles during execution of instruction is the compensation value summed
with the value in the “~” column.
Operation
Indicates operation of instruction.
LH
Indicates special operations involving bits 15 through 08 of the accumulator.
Z:........Transfers “0”.
X: .......Sign-extended transfer through sign extension.
-: .........Transfers nothing.
AH
Indicates special operations involving the high-order 16 bits in the accumulator.
*: ........Transfers from AL to AH.
-: .........No transfer.
Z:........Transfers 00 to AH.
X: .......Transfers 00H or FFH to AH using sign extension AL.
I
Indicates the status of each of the following flags: I (interrupt enable), S (stack), T (sticky bit),
N (negative), Z (zero), V (overflow), and C (carry).
*: ........Changes due to execution of instruction.
-: .........No change.
S: ........Set by execution of instruction.
R: .......Reset by execution of instruction.
S
T
N
Z
V
C
RMW
Indicates whether the instruction is a read-modify-write instruction (a single instruction that
reads data from memory, etc., processes the data, and then writes the result to memory.).
*: ........Instruction is a read-modify-write instruction
-: .........Instruction is not a read-modify-write instruction
Note: A read-modify-write instruction cannot be used on addresses that have different mean-
ings depending on whether they are read or written.