ZiLOG Z8 Technical Manual

SRP src
Instruction for.at:
SRP
Set Register Pointer
Cycles
OPC
(Hex)
Address Mode
arc
~ _______ oP_c ______ ~1 I~ ______ s_r_c ______ ~
6 31 1M
Operation:
flags:
EXanlple:
RP <-- src
The specified value is loaded into bits 4-7 of the Register Pointer (RP) (control
register 253). Bits 0-3 of the RP are always set to O. The source data (with bits
0-3 forced to 0) is the starting address of a working-register group. The
working-register group starting addresses are:
Hex
Decimal
%00 0
%10 16
%20
32
%30 48
%40 64
%50 80
%60 96
%70 112
%FO
240
(control and
peripheral registers)
Values in the range %80-EO are invalid.
No flags affected
Assume the RP currently addresses the control and peripheral register group and the
program has just entered an interrupt service routine. The statement
SRP 11%70
saves the contents of the control and peripheral registers by setting the RP to %70
(01110000), or 112 decimaL Any reference to working registers in the interrupt
routine will point to registers 112-127.
5-45

ZiLOG Z8 Specifications

General

Brand	ZiLOG
Model	Z8
Category	Desktop
Language	English