4501_M Datasheet, PDF (84/212 Pages) Renesas Technology Corp – 4-BIT CISC SINGLE-CHIP MICROCOMPUTER 4500 SERIES

4501 Group
HARDWARE
INSTRUCTIONS
MACHINE INSTRUCTIONS (INDEX BY ALPHABET) (continued)
RD (Reset port D specified by register Y)
Instruction
code
D9
D0
Number of Number of Flag CY
0000010100
014
words
cycles
2
16
1
1
–
Skip condition
–
Operation:
(D(Y)) ← 0
However,
(Y) = 0 to 3
Grouping:
Description:
Note:
Input/Output operation
Clears (0) to a bit of port D specified by register
Y.
Set 0 to 3 to register Y because port D is
four ports (D0–D3).
When values except above are set to regis-
ter Y, this instruction is equivalent to the
NOP instruction.
RT (ReTurn from subroutine)
Instruction
code
D9
D0
Number of Number of Flag CY
0001000100
044
words
cycles
2
16
1
2
–
Skip condition
–
Operation:
(PC) ← (SK(SP))
(SP) ← (SP) – 1
Grouping: Return operation
Description: Returns from subroutine to the routine called
the subroutine.
RTI (ReTurn from Interrupt)
Instruction
code
D9
D0
Number of Number of Flag CY
0001000110
046
words
cycles
2
16
1
1
–
Skip condition
–
Operation:
(PC) ← (SK(SP))
(SP) ← (SP) – 1
Grouping:
Description:
Return operation
Returns from interrupt service routine to
main routine.
Returns each value of data pointer (X, Y, Z),
carry flag, skip status, NOP mode status by
the continuous description of the LA/LXY in-
struction, register A and register B to the
states just before interrupt.
RTS (ReTurn from subroutine and Skip)
Instruction
code
D9
D0
Number of Number of Flag CY Skip condition
0001000101
045
2
16
words
1
cycles
2
–
Skip at uncondition
Operation:
(PC) ← (SK(SP))
(SP) ← (SP) – 1
Grouping:
Description:
Return operation
Returns from subroutine to the routine called
the subroutine, and skips the next instruction
at uncondition.
Rev.2.01 Feb 07, 2005
REJ09B0192-0201
1-72