poor man's _toascii routine, contributed by Fatih Aygun

[cc65] / libsrc / c16 / crt0.s

diff --git a/libsrc/c16/crt0.s b/libsrc/c16/crt0.s
index c7916b9d2a8496f6404dadf33f9503a532feef40..9ac67f8f3725476c678d5419ca8c007b9c1eb204 100644 (file)
--- a/libsrc/c16/crt0.s
+++ b/libsrc/c16/crt0.s
@@ -1,39 +1,43 @@
 ;
 ; Startup code for cc65 (C16 version)
 ;
-; This must be the *first* file on the linker command line
-;                            
 ; Note: The C16 is actually the Plus/4 with just 16KB of memory. So many
 ; things are similar here, and we even use the plus4.inc include file.
 ;
 
        .export         _exit
-       .import         initlib, donelib
-       .import         push0, _main, zerobss
+        .export         __STARTUP__ : absolute = 1      ; Mark as startup
+       .import         initlib, donelib, callirq
+       .import         callmain, zerobss
         .import         MEMTOP, RESTOR, BSOUT, CLRCH
+       .import         __INTERRUPTOR_COUNT__
 
         .include        "zeropage.inc"
-       .include        "../plus4/plus4.inc"
+       .include        "plus4.inc"
 
 
 ; ------------------------------------------------------------------------
-; BASIC header with a SYS call
+; Place the startup code in a special segment.
+
+.segment               "STARTUP"
 
-.code
+; BASIC header with a SYS call
 
-       .org    $0FFF
         .word   Head            ; Load address
 Head:   .word   @Next
-        .word   1000            ; Line number
-        .byte   $9E,"4109"     ; SYS 4109
+        .word   .version        ; Line number
+        .byte   $9E             ; SYS token
+        .byte   <(((Start / 1000) .mod 10) + $30)
+        .byte   <(((Start /  100) .mod 10) + $30)
+        .byte   <(((Start /   10) .mod 10) + $30)
+        .byte   <(((Start /    1) .mod 10) + $30)
         .byte   $00             ; End of BASIC line
 @Next:  .word   0               ; BASIC end marker
-       .reloc
 
 ; ------------------------------------------------------------------------
 ; Actual code
 
-               ldx     #zpspace-1
+Start:  ldx    #zpspace-1
 L1:    lda     sp,x
        sta     zpsave,x        ; save the zero page locations we need
        dex
@@ -66,44 +70,89 @@ L1: lda     sp,x
 MemOk: stx     sp
        sty     sp+1            ; set argument stack ptr
 
-; Call module constructors
+; If we have IRQ functions, chain our stub into the IRQ vector
+
+        lda     #<__INTERRUPTOR_COUNT__
+       beq     NoIRQ1
+       lda     IRQVec
+               ldx     IRQVec+1
+       sta     IRQInd+1
+       stx     IRQInd+2
+       lda     #<IRQStub
+       ldx     #>IRQStub
+       sei
+       sta     IRQVec
+       stx     IRQVec+1
+       cli
 
-       jsr     initlib
+; Call module constructors
 
-; Pass an empty command line
+NoIRQ1: jsr     initlib
 
-               jsr     push0           ; argc
-       jsr     push0           ; argv
+; Push arguments and call main()
 
-       ldy     #4              ; Argument size
-               jsr     _main           ; call the users code
+               jsr     callmain
 
 ; Call module destructors. This is also the _exit entry.
 
-_exit: jsr     donelib         ; Run module destructors
+_exit:         pha                     ; Save the return code on stack
+       jsr     donelib         ; Run module destructors
 
-; Restore system stuff
+; Reset the IRQ vector if we chained it.
 
-       ldx     spsave
-       txs
+        pha                    ; Save the return code on stack
+       lda     #<__INTERRUPTOR_COUNT__
+       beq     NoIRQ2
+       lda     IRQInd+1
+       ldx     IRQInd+2
+       sei
+       sta     IRQVec
+       stx     IRQVec+1
+       cli
 
 ; Copy back the zero page stuff
 
-       ldx     #zpspace-1
+NoIRQ2: ldx     #zpspace-1
 L2:    lda     zpsave,x
        sta     sp,x
        dex
                bpl     L2
 
+; Store the return code into ST
+
+       pla
+       sta     ST
+
+; Restore the stack pointer
+
+       ldx     spsave
+       txs
+
 ; Reset changed vectors
 
        jmp     RESTOR
 
+; ------------------------------------------------------------------------
+; The IRQ vector jumps here, if condes routines are defined with type 2.
+
+IRQStub:
+       cld                             ; Just to be sure
+               jsr     callirq                 ; Call the functions
+               jmp     IRQInd                  ; Jump to the saved IRQ vector
+
+; ------------------------------------------------------------------------
+; Data
 
 .data
+
+IRQInd: jmp     $0000
+
+.segment        "ZPSAVE"
+
 zpsave:        .res    zpspace
 
 .bss
+
 spsave:        .res    1