Rabbit 2000 - Page 29

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,wheremn 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 nm 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
- - - -