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|
||| -*- mode: gas; gas-comment-char: 124 -*-
||| z80 emulator for 68k calculators
||| Astrid Smith
||| Project started: 2010-06-06
||| GPL
||| Yes, I use lots of big ascii art. With this much code, you need
||| something to catch your eye when scrolling through it. I suppose
||| I'll split it into different files later.
||| Registers used:
|||
||| A7 68000 stack pointer
||| A6/epc emulated PC
||| A5 instruction table base pointer
||| A4/esp emulated SP
||| A3 pointer to flag_storage
||| A2
||| A1
||| A0
|||
||| D0 current instruction, scratch for macros
||| D1 scratch for instructions
||| D2 further scratch
|||
|||
||| The following have their shadows in the top half of the register
||| D3/eaf = AF A is in the low byte, F in the high byte (yeah ... speed)
||| D4/ebc = BC B high, C low
||| D5/ede = DE D high, E low
||| D6/ehl = HL H high, L low
|||
||| IY is used more often so it's easier to get at. It can be slow
||| but I don't really care to go to the effort to make it so.
||| D7/eixy = IX (hi word), IY (low word)
||| emulated I and R are both in RAM
.xdef _ti89
|.xdef _ti92plus
.xdef __main
|.xdef _tigcc_native
.include "./tios.inc"
.include "global.inc"
__main:
movem.l d0-d7/a0-a6,-(sp)
bsr init_load
bsr display_setup
bsr emu_setup
lea emu_plain_op,a5
|| ... aaaaand we're off!
jsr emu_run
bsr emu_teardown
bsr display_teardown
bsr unload
movem.l (sp)+,d0-d7/a0-a6
rts
.include "ports.s"
.include "interrupts.s"
.include "flags.s"
.include "alu.s"
emu_setup:
movea.l emu_op_00,a5
lea emu_run,a2
lea flag_storage,a3
move.w #0x4000,d1
bsr deref
move.l a0,epc
move.l a0,esp
rts
emu_teardown:
rts
.include "memory.s"
|| =========================================================================
|| instruction instruction instruction ================================
|| _ _ _ _ ================================
|| __| (_)___ _ __ __ _| |_ ___| |__ ================================
|| / _` | / __| '_ \ / _` | __/ __| '_ \ ================================
|| | (_| | \__ \ |_) | (_| | || (__| | | | ================================
|| \__,_|_|___/ .__/ \__,_|\__\___|_| |_| ================================
|| |_| =================================
|| ========== ========================================================
|| =========================================================================
.include "opcodes.s"
emu_run:
|| XXX: make this actually return
DONE
rts
emu_op_undo_cb:
emu_op_undo_dd:
emu_op_undo_ed:
emu_op_undo_fd:
rts
|
