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 ; Set up the CPU and System-IRQ
47 csh ; Set high speed CPU mode
52 ; Set up stack and memory mapping
53 ldx #$FF ; Stack top ($21FF)
56 ; At startup all MPRs are set to 0, so init them
58 tam #%00000001 ; 0000-1FFF = Hardware page
60 tam #%00000010 ; 2000-3FFF = Work RAM
62 ; FIXME: setup a larger block of memory to use with C-code
64 ;tam #%00000100 ; 4000-5FFF = Save RAM
66 ;tam #%00001000 ; 6000-7FFF Page 2
68 ;tam #%00010000 ; 8000-9FFF Page 3
70 ;tam #%00100000 ; A000-BFFF Page 4
72 ;tam #%01000000 ; C000-DFFF Page 5
74 ;tam #%10000000 ; e000-fFFF hucard/syscard bank 0
76 ; Clear work RAM (2000-3FFF)
78 tii $2000, $2001, $1FFF
81 stz TIMER_CTRL ; Timer off
83 sta IRQ_MASK ; Interrupts off
84 stz IRQ_STATUS ; Acknowledge timer
86 ; FIXME; i dont know why the heck this one doesnt work when called from a constructor :/
90 ; Turn on background and VD interrupt/IRQ1
92 sta IRQ_MASK ; IRQ1=on
97 ; Copy the .data segment to RAM
98 tii __DATA_LOAD__, __DATA_RUN__, __DATA_SIZE__
101 lda #<(__RAM_START__+__RAM_SIZE__)
102 ldx #>(__RAM_START__+__RAM_SIZE__)
106 ; Call module constructors
109 cli ; allow IRQ only after constructors have run
111 ; Pass an empty command line
115 ldy #4 ; Argument size
116 jsr _main ; Call the users code
118 ; Call module destructors. This is also the _exit entry.
120 jsr donelib ; Run module destructors
122 ; reset the PCEngine (start over)
132 ; ------------------------------------------------------------------------
134 ; ------------------------------------------------------------------------
137 .word IRQStub ; $fff6 IRQ2 (External IRQ, BRK)
138 .word IRQStub ; $fff8 IRQ1 (VDC)
139 .word IRQStub ; $fffa Timer
140 .word _nmi ; $fffc NMI
141 .word start ; $fffe reset