; -------------------------------------------------------
;
; 56836E_init.asm
;
; Metrowerks, a Freescale company
; sample code
;
; description: main entry point to C code.
; setup runtime for C and call main
;
; -------------------------------------------------------
;===============================
; OMR mode bits
;===============================
NL_MODE EQU $8000
CM_MODE EQU $0100
XP_MODE EQU $0080
R_MODE EQU $0020
SA_MODE EQU $0010
;===============================
; init
;===============================
section startup
XREF F_stack_addr
XREF F_xROM_to_xRAM
XREF F_pROM_to_xRAM
XREF F_Ldata_size
XREF F_Ldata_ROM_addr
XREF F_Ldata_RAM_addr
org p:
GLOBAL Finit_56800_
SUBROUTINE "Finit_56800_",Finit_56800_,Finit_56800_END-Finit_56800_
Finit_56800_:
;
; setup the OMr with the values required by C
;
bfset #NL_MODE,omr ; ensure NL=1 (enables nsted DO loops)
nop
nop
bfclr #(CM_MODE|XP_MODE|R_MODE|SA_MODE),omr ; ensure CM=0 (optional for C)
; ensure XP=0 to enable harvard architecture
; ensure R=0 (required for C)
; ensure SA=0 (required for C)
; setup the m01 register for linear addressing
move.w #-1,x0
moveu.w x0,m01 ; set the m register to linear addressing
moveu.w hws,la ; clear the hardware stack
moveu.w hws,la
nop
nop
CALLMAIN: ; initialize compiler environment
; initialize the Stack
move.l #>>F_Lstack_addr,r0
bftsth #$0001,r0
bcc noinc
adda #1,r0
noinc:
tfra r0,sp ; set stack pointer too
move.w #0,r1
nop
move.w r1,x:(sp)
adda #1,sp
jsr F__init_sections ; clear BSS
; xROM-to-xRAM utility
nop
move.w #F_xROM_to_xRAM,r0 ; check for the option
tst.w r0
beq end_xrom2xram ; if no xROM-to-xRAM, then exit
nop
move.l #>>F_Ldata_size,r2 ; set data size
move.l #>>F_Ldata_ROM_addr,r3 ; src address -- xROM data start
move.l #>>F_Ldata_RAM_addr,r1 ; dest address -- xRAM data start
do r2,>>end_xrom2xram ; copy for r2 times
move.w x:(r3)+,x0 ; fetch value at address r3
nop
nop
nop
move.w x0,x:(r1)+ ; stash value at address r1
end_xrom2xram:
; pROM-to-xRAM utility
nop
move.w #F_pROM_to_xRAM,r0 ; check for the option
tst.w r0
beq end_prom2xram ; if no pROM-to-xRAM, then exit
nop
move.l #>>F_Ldata_size,r2 ; set data size
move.l #>>F_Ldata_ROM_addr,r3 ; src address -- pROM data start
move.l #>>F_Ldata_RAM_addr,r1 ; dest address -- xRAM data start
do r2,>>end_prom2xram ; copy for r2 times
move.w p:(r3)+,x0 ; fetch value at address r3
nop
nop
nop
move.w x0,x:(r1)+ ; stash value at address r1
end_prom2xram:
; call main()
move.w #0,y0 ; pass parameters to main()
move.w #0,R2
move.w #0,R3
jsr Fmain ; call the user program
;
; The fflush calls where removed because they added code
; growth in cases where the user is not using any debugger IO.
; Users should now make these calls at the end of main if they use debugger IO
;
; move.w #0,r2
; jsr Ffflush ; flush file IO
; jsr Ffflush_console ; flush console IO
; end of program; halt CPU
debughlt
rts
Finit_56800_END:
endsec
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