Epson S1C63000 PUSH %ir, RET, 1 cycle, 1 cycle, Return from subroutine, Push ir reg. onto stack

CHAPTER 4: INSTRUCTION SET

PUSH %ir			Push ir reg. onto stack																		1 cycle
Function: ([(SP1-1)*4+3]~[(SP1-1)*4]) ←								ir, SP1 ←			SP1 -1
	Decrements the stack pointer SP1, then stores the content of the ir register (X or Y) into the
	addresses (4 words) indicated by the SP1 (SP1 indicates the lowest address).
Code:	Mnemonic		MSB															LSB
	PUSH %X			1		1	1		1	1	1	1	1	0	0	0	0		1	1FE1H
	PUSH %Y			1		1	1		1	1	1	1	1	0	0	0	1		X	1FE2H, (1FE3H)
Flags:	E	I	C		Z
	↓	–	–		–
Mode:	Register direct
	Extended addressing: Invalid

RET

Return from subroutine

1 cycle

Function: PC ← ([SP1*4+3]~[SP1*4]), SP1 ←

SP1 +1

Loads the 16-bit data (return address) that has been stored in the addresses (4 words) indicated

by the stack pointer SP1 (SP1 indicates the lowest address) into the PC to return from the

subroutine. The SP1 is incremented.

Code:

Mnemonic

MSB

LSB

RET

1

1

1

1

1

1

1

1

1

1

0

X

0

1FF8H, (1FFAH)

Flags:

E

I

C

Z

↓

–

–

–

118 EPSON S1C63000 CORE CPU MANUAL