Difference between revisions of "PM Opc RET"
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(RET Instruction) |
(RET* takes 16 cycles) |
||
| Line 8: | Line 8: | ||
|F8 | |F8 | ||
|RET | |RET | ||
| − | | | + | |16 |
|- | |- | ||
|F9 | |F9 | ||
|RETI | |RETI | ||
| − | | | + | |16 |
|- | |- | ||
|FA | |FA | ||
|RETSKIP | |RETSKIP | ||
| − | | | + | |16 |
|} | |} | ||
Revision as of 02:41, 28 October 2010
RET = Return from routine
| Hex | Mnemonic | Cycles |
|---|---|---|
| F8 | RET | 16 |
| F9 | RETI | 16 |
| FA | RETSKIP | 16 |
Execute
F = Register F U/V = Register U or V SP = Register SP (Stack Pointer) PC = Register PC (Program Counter)
; RET (Return from a subroutine) V = Memory[SP+2] PC = (Memory[SP+1] SHL 8) + Memory[SP] SP = SP - 3
; RETI (Return from an interrupt) V = Memory[SP+3] PC = (Memory[SP+2] SHL 8) + Memory[SP+1] F = Memory[SP] SP = SP - 4
; RETSKIP (Return from a subroutine and skip 2 bytes) V = Memory[SP+2] PC = (Memory[SP+1] SHL 8) + Memory[SP] + 2 SP = SP - 3
Description
Return from a subroutine or an interrupt.
Conditions
None
Examples
; A = 0x10 ; B = 0x10 CALL somefunction ; A = 0x11 ; B = 0x0F (...) somefunction: INC A DEC B RET INC A ; Never executed
