Instruction Reference Manual
25
Description
If the data in index register IX or IY does not equal zero, then that register is set to 1. These instructions are
implemented for the Rabbit and are not available for the Z180.
Description
This instruction is used to call a subroutine. First the data in the Program Counter is pushed onto the stack.
The high-order byte of the PC is pushed first, then the low-order byte. The program counter is then loaded
with mn,16-bit address of the first instruction of the subroutine. The Stack Pointer is updated to reflect the two
bytes pushed onto the stack.
The Dynamic C assembler recognizes
CALL label
, where
mn
is coded as a label.
BOOL IX
BOOL IY
Opcode
Instruction
Clocks
Operation
DD CC
BOOL IX
4 (2,2)
If (IX != 0) IX = 1
FD CC
BOOL IY
4 (2,2)
If (IY != 0) IY = 1
Flags
ALTD
I/O
S
Z
L/V
C
F
R
SP
S
D
•
•
0
0
•
CALL mn
Opcode
Instruction
Clocks
Operation
CD n m
CALL mn
12 (2,2,2,3,3)
(SP - 1) = PC
(high)
;
(SP - 2) = PC
(low)
;
PC = mn; SP = SP - 2
Flags
ALTD
I/O
S
Z
L/V
C
F
R
SP
S
D
-
-
-
-
Содержание 2000
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