;Boot stub for loading BASIC programs from short ATR files. ;(c) 1998-1999 Jindrich Kubec ; 20070524 bkw: modified to assemble with dasm processor 6502 SIOV = $E459 DOSVEC = $0A RAMTOP = $6A LOMEM = $80 BOOT = $09 BASICF = $03F8 PORTB = $D301 EOPEN = $EF94 BAS_CONT = $A97A BAS_EXEC = $B755 LOADER_START = $0700 LOADER_END = $0800 BASMEMSTART = $0700 BASPTRSLEN = $0E BASPTRSSTART = LOADER_END - BASPTRSLEN org LOADER_START BOOTST: .byte 0 .byte (ENDBOOT-BOOTST+127)/128 .WORD *-2 .WORD MAIN_BEG CLC RTS_INSTR: RTS ;used for extractor ORI_LEN: .WORD 0 MAIN_BEG: LDX #

header JSR $C642 LDX #padding JSR $C642 ;copy pointers to correct area, add $700 LDX #BASPTRSLEN - 1 SETVECT: CLC LDA BASPTRSSTART,X ADC #>BASMEMSTART STA LOMEM,X DEX LDA BASPTRSSTART,X STA LOMEM,X DEX BPL SETVECT LDA #$31 ;D STA $300 LDA #$01 ;1 STA $301 LDA #$52 ;read STA $302 LDA #$80 ;$80 bytes STA $308 LDA #$00 STA $309 STA $30B LDA $82 ;buffer address STA $304 LDA $83 STA $305 ;starting sector LDA # ( (ENDBOOT-BOOTST+127)/128 ) +1 STA $30A SIO_CONT: LDA #$40 ;read STA $303 JSR SIOV LDA $303 CMP #$01 BEQ NOERR JSR $C63E AGAIN: JMP AGAIN ;dynamic halt ;move buffer pointer NOERR: ;LDA $304 ;CLC ;ADC $308 ;STA $304 ;LDA $305 ;ADC $309 ;STA $305 ;this does the same as the above, but is shorter CLC LDX #$FE LP0: LDA $304 - $FE,X ADC $308 - $FE,X STA $304 - $FE,X INX BNE LP0 ;increment sector number INC $30A BNE NX1 INC $30B NX1: ;decrement number of sectors to load LDA SECTORS BNE NX2 DEC SECTORS+1 BMI BAS_RUN NX2: DEC SECTORS JMP SIO_CONT BAS_RUN: LDX #$FF TXS LDA #$0A STA $C9 LDA #$00 STA BOOT STA BASICF ;turn on basic LDA #$FD STA PORTB ;set stack LDA #>BAS_CONT PHA LDA #BAS_EXEC PHA LDA #