mirror of https://github.com/trudnai/Steve2.git
79 lines
1.7 KiB
C
79 lines
1.7 KiB
C
//
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// main.c
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// 6502
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//
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// Created by Tamas Rudnai on 7/14/19.
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// Copyright © 2019 GameAlloy. All rights reserved.
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//
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#ifndef __6502_INSTR_CALL_RET_JUMP_H__
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#define __6502_INSTR_CALL_RET_JUMP_H__
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/**
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JMP Jump to New Location
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(PC+1) -> PCL N Z C I D V
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(PC+2) -> PCH - - - - - -
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addressing assembler opc bytes cyles
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--------------------------------------------
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absolute JMP oper 4C 3 3
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indirect JMP (oper) 6C 3 5
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**/
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static inline void JMP( uint16_t addr ) {
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dbgPrintf("JMP %04X ", addr);
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m6502.pc = addr;
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}
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/**
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JSR Jump to New Location Saving Return Address
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push (PC+2), N Z C I D V
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(PC+1) -> PCL - - - - - -
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(PC+2) -> PCH
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addressing assembler opc bytes cyles
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--------------------------------------------
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absolute JSR oper 20 3 6
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**/
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static inline void JSR( uint16_t addr ) {
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dbgPrintf("JSR ");
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PUSH_addr(m6502.pc);
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JMP( addr );
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}
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/**
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RTS Return from Subroutine
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pull PC, PC+1 -> PC N Z C I D V
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- - - - - -
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addressing assembler opc bytes cyles
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--------------------------------------------
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implied RTS 60 1 6
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**/
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static inline void RTS() {
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dbgPrintf("RTS ");
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JMP( POP_addr() );
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}
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/**
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RTI Return from Interrupt
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pull SR, pull PC N Z C I D V
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from stack
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addressing assembler opc bytes cyles
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--------------------------------------------
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implied RTI 40 1 6
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**/
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static inline void RTI() {
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dbgPrintf("RTI ");
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m6502.sr = POP();
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RTS();
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}
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#endif // __6502_INSTR_CALL_RET_JUMP_H__
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