s1mp3_crt0.asm

s1mp3 sdk, action mp3 develop tool kit!

; Startup Code for Embedded Targets
;
;	Daniel Wallner March 2002
;
;	$Id: crt0.asm,v 1.3 2005/12/13 18:44:26 aaron Exp $
;
;       02/03/2006 01:44 fc: code length is now fixed by conv.exe
;                            added support for floating points.
;                            added support for heap (due to the fp support).

;-------
; Some general scope declarations
;-------

        XREF    _main           ;main() is always external to crt0 code
        ;XREF    ram_start
     
;-------------------------------------------------------------------------------
; definitions
;-------------------------------------------------------------------------------

	DEFC	Header_Length = 0x0600
	DEFC	Application_Start = Header_Length

	DEFC	Stack_Top = 0x8000				; Stack starts at 0x8000
	DEFC    Stack_Size = 0x0800				; 2k of stack
	DEFC	HEAP_Start = (Stack_Top - Stack_Size * 2)	; Heap starts at 0x7000
	DEFC	HEAP_Length = Stack_Size			; 2k of heap
	
	MODULE  crt0

.header
	DEFW    0x0050                          ; header id
	DEFW    0x4757                          ;
	DEFW    0x9719                          ;
	DEFW    0x0003                          ;
	DEFW    Header_Length                   ; text fileoffset (lo)
	DEFW    0                               ; text fileoffset (hi)
	DEFW    0				; Entry point (will be fixed by conv.exe)
	DEFW    Application_Start		; text address
	DEFW    0                 		; data fileoffset (lo)
	DEFW    0                 		; data fileoffset (hi)
	DEFW    0                 		; data length
	DEFW    0                 		; data address
	DEFW    0                 		; bss length
	DEFW    0                 		; bss address
	DEFW    start   	  		; entry point
	DEFB    0                 		; entry bank
	DEFB    0                 		; number of banks
	DEFS    (Header_Length - ASMPC)

;-------------------------------------------------------------------------------
; code segment
;-------------------------------------------------------------------------------
.start	;push	bc
	;push	de

	; Switch all interrupts off
	di
	xor	a
	out     (0x27), a							; MINT_ENABLE_REG

	ld	hl, Stack_Top
	ld	sp, hl

	; Clear heap memory
	ld	hl, HEAP_Start
	ld	de, HEAP_Start + 1
	ld	bc, HEAP_Length - 1
	ld	(hl), 0
	ldir

	; Save the stack for exit()
	ld      (exitsp),sp

;;IF !DEFINED_nostreams
;;IF DEFINED_ANSIstdio
;; Set up the std* stuff so we can be called again
;;	ld	hl,__sgoioblk+2
;;	ld	(hl),19	;stdin
;;	ld	hl,__sgoioblk+6
;;	ld	(hl),21	;stdout
;;	ld	hl,__sgoioblk+10
;;	ld	(hl),21	;stderr
;;ENDIF
;;ENDIF

;;	ld      hl,$8080
;;	ld      (fp_seed),hl
;;	xor     a
;;	ld      (exitcount),a

; Entry to the user code
	call    _main

.cleanup
	;pop     af
	;pop     bc
;	pop	de
;	pop	bc
	;ex      de, hl
	;ex      (sp), hl
	;ex      de, hl
	;push    hl
	;ld      hl, 0x1008
	;rst     0x10
	;pop     hl
	;pop     de
	ret     
;
;       Deallocate memory which has been allocated here!
;
;	push	hl
;IF !DEFINED_nostreams
;IF DEFINED_ANSIstdio
	;LIB	closeall
;	call	closeall
;ENDIF
;ENDIF

;.endloop
;	jr	endloop
;.l_dcal
;	jp      (hl)

;---------------------------------
; Select which printf core we want
;---------------------------------
._vfprintf
;IF DEFINED_floatstdio
;	LIB	vfprintf_fp
;	jp	vfprintf_fp
;ELSE
;	IF DEFINED_complexstdio
;		LIB	vfprintf_comp
;		jp	vfprintf_comp
;	ELSE
;		IF DEFINED_ministdio
;			LIB	vfprintf_mini
;			jp	vfprintf_mini
;		ENDIF
;	ENDIF
;ENDIF

; Static variables kept in safe workspace

DEFVARS HEAP_Start
{
__sgoioblk      ds.b    40      ;stdio control block
int_seed        ds.w    1       ;Integer seed
oldsp		ds.w	1
exitsp          ds.w    1       ;atexit() stack
exitcount       ds.b    1       ;Number of atexit() routines
fp_seed         ds.w    3       ;Floating point seed (not used ATM)
extra           ds.w    3       ;Floating point spare register
fa              ds.w    3       ;Floating point accumulator
fasign          ds.b    1       ;Floating point variable
heapblocks      ds.w    1       ;Number of free blocks
heaplast        ds.w    1       ;Pointer to linked blocks
}

;--------
; Now, include the math routines if needed..
;--------
;IF NEED_floatpack
        INCLUDE "#float.asm"
;ENDIF