2 ; Startup code for cc65 (PCEngine version)
4 ; by Groepaz/Hitmen <groepaz@gmx.net>
5 ; based on code by Ullrich von Bassewitz <uz@cc65.org>
7 ; This must be the *first* file on the linker command line
11 .export __STARTUP__ : absolute = 1 ; Mark as startup
13 .import initlib, donelib
14 .import push0, _main, zerobss
16 .import tmp1,tmp2,tmp3
19 .import __RAM_START__, __RAM_SIZE__
20 .import __ROM0_START__, __ROM0_SIZE__
21 .import __ROM_START__, __ROM_SIZE__
22 .import __STARTUP_LOAD__,__STARTUP_RUN__, __STARTUP_SIZE__
23 .import __CODE_LOAD__,__CODE_RUN__, __CODE_SIZE__
24 .import __RODATA_LOAD__,__RODATA_RUN__, __RODATA_SIZE__
25 .import __DATA_LOAD__,__DATA_RUN__, __DATA_SIZE__
33 ; ------------------------------------------------------------------------
34 ; Place the startup code in a special segment.
40 ; setup the CPU and System-IRQ
46 csh ; set high speed CPU mode
51 ; Setup stack and memory mapping
52 ldx #$FF ; Stack top ($21FF)
55 ; at startup all MPRs are set to 0, so init them
57 tam #%00000001 ; 0000-1FFF = Hardware page
59 tam #%00000010 ; 2000-3FFF = Work RAM
61 ; FIXME: setup a larger block of memory to use with C-code
63 ;tam #%00000100 ; 4000-5FFF = Save RAM
65 ;tam #%00001000 ; 6000-7FFF Page 2
67 ;tam #%00010000 ; 8000-9FFF Page 3
69 ;tam #%00100000 ; A000-BFFF Page 4
71 ;tam #%01000000 ; C000-DFFF Page 5
73 ;tam #%10000000 ; e000-fFFF hucard/syscard bank 0
75 ; Clear work RAM (2000-3FFF)
77 tii $2000, $2001, $1FFF
80 stz TIMER_COUNT ; Timer off
82 sta IRQ_MASK ; Interrupts off
83 stz IRQ_STATUS ; Acknowledge timer
85 ; FIXME; i dont know why the heck this one doesnt work when called from a constructor :/
89 ; Turn on background and VD interrupt/IRQ1
91 sta IRQ_MASK ; IRQ1=on
96 ; Copy the .data segment to RAM
106 ldx #>(__DATA_SIZE__)
108 beq @s1 ; no more full pages
124 ; copy remaining bytes
132 cpy #<(__DATA_SIZE__)
136 lda #<(__RAM_START__+__RAM_SIZE__)
138 lda #>(__RAM_START__+__RAM_SIZE__)
141 ; Call module constructors
144 cli ; allow IRQ only after constructors have run
146 ; Pass an empty command line
150 ldy #4 ; Argument size
151 jsr _main ; call the users code
153 ; Call module destructors. This is also the _exit entry.
155 jsr donelib ; Run module destructors
157 ; reset the PCEngine (start over)
160 ; ------------------------------------------------------------------------
161 ; System V-Blank Interupt
162 ; FIXME: hooks should be provided so the user can abuse the IRQ
163 ; ------------------------------------------------------------------------
170 ; increment the system tick counter
179 ; Acknowlege interrupt
198 ; ------------------------------------------------------------------------
200 ; ------------------------------------------------------------------------
203 .word _irq2 ; $fff6 IRQ2 (External IRQ, BRK)
204 .word _irq1 ; $fff8 IRQ1 (VDC)
205 .word _timer ; $fffa Timer
206 .word _nmi ; $fffc NMI
207 .word start ; $fffe reset