Zilog Z80380 - Manual (Page 65)

5-31
Z380 ™
U SER ' S M ANUAL Z ILOG
DC-8297-03
CALL
CALL
CALL [cc,]dst dst = DA
Operation: if (cc is TRUE) then begin
if (XM) then begin
SP
←
SP - 4
(SP)
←
PC(7-0)
(SP+1)
←
PC(15-8)
(SP+2)
←
PC(23-16)
(SP+3)
←
PC(31-24)
PC(31-0)
←
dst(31-0)
else begin
SP
←
SP - 2
(SP)
←
PC(7-0)
(SP+1)
←
PC(15-8)
PC(15-0)
←
dst(15-0)
end
end
A conditional Call transfers program control to the destination address if the setting of a
selected flag satisfies the condition code “cc” specified in the instruction; an Unconditional
Call always transfers control to the destination address. The current contents of the Program
Counter (PC) are pushed onto the top of the stack; the PC value used is the address of the
first instruction byte following the Call instruction. The destination address is then loaded
into the PC and points to the first instruction of the called procedure. At the end of a
procedure a Return instruction (RET) can be used to return to the original program.
Each of the Zero, Carry, Sign, and Overflow Flags can be individually tested and a call
performed conditionally on the setting of the flag.
The operand is not enclosed in parentheses with the CALL instruction.
Flags: S: Unaffected
Z: Unaffected
H: Unaffected
V: Unaffected
N: Unaffected
C: Unaffected
Addressing Execute
Mode Syntax Instruction Format Time Note
DA: CALL CC,addr 11-cc100 -a(low)- -a(high) note I, X
CALL addr 11001101 -a(low)- -a(high) 4+w I, X
Field Encodings: cc: 000 for NZ, 001 for Z, 010 for NC, 011 for C,
100 for PO or NV, 101 for PE or V, 110 for P or NS, 111 for M or S
Note: 2 if CC is false, 4+w if CC is true