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
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 .importzp tmp1,tmp2,tmp3
35 ; ------------------------------------------------------------------------
36 ; Place the startup code in a special segment.
42 ; setup the CPU and System-IRQ
48 csh ; set high speed CPU mode
53 ; Setup stack and memory mapping
54 ldx #$FF ; Stack top ($21FF)
57 ; at startup all MPRs are set to 0, so init them
59 tam #%00000001 ; 0000-1FFF = Hardware page
61 tam #%00000010 ; 2000-3FFF = Work RAM
63 ; FIXME: setup a larger block of memory to use with C-code
65 ;tam #%00000100 ; 4000-5FFF = Save RAM
67 ;tam #%00001000 ; 6000-7FFF Page 2
69 ;tam #%00010000 ; 8000-9FFF Page 3
71 ;tam #%00100000 ; A000-BFFF Page 4
73 ;tam #%01000000 ; C000-DFFF Page 5
75 ;tam #%10000000 ; e000-fFFF hucard/syscard bank 0
77 ; Clear work RAM (2000-3FFF)
79 tii $2000, $2001, $1FFF
82 stz TIMER_CTRL ; Timer off
84 sta IRQ_MASK ; Interrupts off
85 stz IRQ_STATUS ; Acknowledge timer
87 ; FIXME; i dont know why the heck this one doesnt work when called from a constructor :/
91 ; Turn on background and VD interrupt/IRQ1
93 sta IRQ_MASK ; IRQ1=on
98 ; Copy the .data segment to RAM
99 tii __DATA_LOAD__, __DATA_RUN__, __DATA_SIZE__
102 lda #<(__RAM_START__+__RAM_SIZE__)
104 lda #>(__RAM_START__+__RAM_SIZE__)
107 ; Call module constructors
110 cli ; allow IRQ only after constructors have run
112 ; Pass an empty command line
116 ldy #4 ; Argument size
117 jsr _main ; call the users code
119 ; Call module destructors. This is also the _exit entry.
121 jsr donelib ; Run module destructors
123 ; reset the PCEngine (start over)
133 ; ------------------------------------------------------------------------
135 ; ------------------------------------------------------------------------
138 .word IRQStub ; $fff6 IRQ2 (External IRQ, BRK)
139 .word IRQStub ; $fff8 IRQ1 (VDC)
140 .word IRQStub ; $fffa Timer
141 .word _nmi ; $fffc NMI
142 .word start ; $fffe reset