Zilog Z86193 - Manual (Page 171)

Z8
®
CPU
User Manual
UM001604-0108 Instruction Description
164
Call Procedure
Syntax
CALL dst
Instruction Format
Operation
SP
←
SP–2
@SP
←
PC
PC
←
dst
The Stack pointer is decremented by two, the current contents of the Program Counter
(PC) (address of the first instruction following the CALL instruction) are pushed onto the
top of the Stack, and the specified destination address is then loaded into the PC. The PC
now points to the first instruction of the procedure.
At the end of the procedure a RET (return) instruction can be used to return to the original
program flow. RET pops the top of the Stack and replace the original value into the PC.
Address mode IRR can be used to specify a 4-bit Working Register Pair. In this format, the
destination Working Register Pair operand is specified by adding
1110b
(
Eh
) to the high
nibble of the operand. For example, if Working Register Pair RR12 (CH) is the destination
operand, then
ECh
is used as the destination operand in the Op Code.
Cycles
OPC
(Hex)
Address Mode
dst
OPC dst 20 D6 DA
OPC dst 20 D4 IRR
Flag Description
C Unaffected
Z Unaffected
S Unaffected
V Unaffected
D Unaffected
H Unaffected
E src or E dst
Note: