conio.o \
cputc.o \
crt0.o \
+ kacptr.o \
+ kbasin.o \
kbhit.o \
- kernal.o \
+ kbsout.o \
+ kchkin.o \
+ kciout.o \
+ kckout.o \
+ kclall.o \
+ kclose.o \
+ kclrch.o \
+ kiobase.o \
+ klisten.o \
+ kload.o \
+ kopen.o \
+ krdtim.o \
+ kreadst.o \
+ ksave.o \
+ ksetlfs.o \
+ ksetnam.o \
+ ksettim.s \
+ ktalk.o \
+ kunlsn.o \
+ kuntlk.o \
randomize.o \
readjoy.o \
tgi_mode_table.o
.include "plus4.inc"
-
; --------------------------------------------------------------------------
+.segment "LOWMEM" ; Accesses the ROM - must go into low mem
+
_cgetc: lda KEY_COUNT ; Get number of characters
ora FKEY_COUNT ; Or with number of function key chars
bne L2 ; Jump if there are already chars waiting
sta TED_CURSLO ; Cursor off
sta TED_CURSHI
-L2: jsr KBDREAD ; Read char and return in A
+L2: sta ENABLE_ROM ; Bank in the ROM
+ jsr KBDREAD ; Read char and return in A (ROM routine)
+ sta ENABLE_RAM ; Reenable the RAM
ldx #0
rts
.constructor initkbd
.destructor donekbd
+.code ; Can go into the normal code segment
+
.proc initkbd
ldy #15
.endproc
+.segment "LOWMEM" ; Accesses the ROM - must go into low mem
+
.proc donekbd
ldx #$39 ; Copy the original function keys
+ sta ENABLE_ROM ; Bank in the ROM
@L1: lda FKEY_ORIG,x
sta FKEY_SPACE,x
dex
bpl @L1
+ sta ENABLE_RAM ; Bank out the ROM
rts
.endproc
.include "plus4.inc"
-_clrscr = CLRSCR
+.segment "LOWCODE" ; Must go into low memory
+
+.proc _clrscr
+ sta ENABLE_ROM ; Enable the ROM
+ jsr CLRSCR ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
.export _exit
.import initlib, donelib
.import push0, _main, zerobss
- .import MEMTOP, RESTOR, BSOUT, CLRCH
+ .import __IRQFUNC_TABLE__, __IRQFUNC_COUNT__
.include "zeropage.inc"
.include "plus4.inc"
; ------------------------------------------------------------------------
-; BASIC header with a SYS call
+; Place the startup code in a special segment to cope with the quirks of
+; plus/4 banking.
-.code
+.segment "STARTUP"
- .org $0FFF
.word Head ; Load address
Head: .word @Next
.word 1000 ; Line number
.byte $9E,"4109" ; SYS 4109
.byte $00 ; End of BASIC line
@Next: .word 0 ; BASIC end marker
- .reloc
; ------------------------------------------------------------------------
; Actual code
+ sei ; No interrupts since we're banking out the ROM
+ sta ENABLE_RAM
ldx #zpspace-1
L1: lda sp,x
sta zpsave,x ; save the zero page locations we need
dex
bpl L1
+ sta ENABLE_ROM
+ cli
; Close open files
- jsr CLRCH
+ jsr $FFCC ; CLRCH
; Switch to second charset
lda #14
- jsr BSOUT
+ jsr $FFD2 ; BSOUT
+
+; Setup the IRQ vector in the banked RAM and switch off the ROM
+
+ sei ; No ints, handler not yet in place
+ sta ENABLE_RAM
+ lda #<IRQ
+ sta $FFFE ; Install interrupt handler
+ lda #>IRQ
+ sta $FFFF
+ cli ; Allow interrupts
; Clear the BSS data
jsr zerobss
-; Save system stuff and setup the stack
+; Save system stuff and setup the stack. The stack starts at the top of the
+; usable RAM.
tsx
stx spsave ; save system stk ptr
- sec
- jsr MEMTOP ; Get top memory
- cpy #$80 ; We can only use the low 32K :-(
- bcc MemOk
- ldy #$80
- ldx #$00
-MemOk: stx sp
- sty sp+1 ; set argument stack ptr
+ lda #<$FD00
+ sta sp
+ lda #>$FD00
+ sta sp+1
; Call module constructors
dex
bpl L2
-; Reset changed vectors
+; Enable the ROM, reset changed vectors and return to BASIC
+
+ sta ENABLE_ROM
+ jmp $FF8A ; RESTOR
- jmp RESTOR
+; ------------------------------------------------------------------------
+; IRQ handler
+
+.segment "LOWCODE"
+
+IRQ: pha
+ txa
+ pha
+ tsx ; Get the stack pointer
+ lda $0103,x ; Get the saved status register
+ tax
+ lda #>irqret ; Push new return address
+ pha
+ lda #<irqret
+ pha
+ txa
+ pha
+ sta ENABLE_ROM ; Switch to ROM
+ jmp ($FFFE) ; Jump to kernal irq handler
+
+irqret: sta ENABLE_RAM ; Switch back to RAM
+ pla
+ tax
+ pla
+ rti
+
+; ------------------------------------------------------------------------
+; Data
.data
zpsave: .res zpspace
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; ACPTR replacement function
+;
+
+ .export ACPTR
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc ACPTR
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFA5 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; BASIN replacement function
+;
+
+ .export BASIN
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc BASIN
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFCF ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; BSOUT replacement function
+;
+
+ .export BSOUT
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc BSOUT
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFD2 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; CHKIN replacement function
+;
+
+ .export CHKIN
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc CHKIN
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFC6 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; CIOUT replacement function
+;
+
+ .export CIOUT
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc CIOUT
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFA8 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; CKOUT replacement function
+;
+
+ .export CKOUT
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc CKOUT
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFC9 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; CLALL replacement function
+;
+
+ .export CLALL
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc CLALL
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFE7 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; CLOSE replacement function
+;
+
+ .export CLOSE
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc CLOSE
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFC3 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; CLRCH replacement function
+;
+
+ .export CLRCH
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc CLRCH
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFCC ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
+++ /dev/null
-;
-; Ullrich von Bassewitz, 19.11.2002
-;
-; Plus/4 kernal functions
-;
-
- .export CINT
- .export IOINIT
- .export RAMTAS
- .export RESTOR
- .export VECTOR
- .export SETMSG
- .export SECOND
- .export TKSA
- .export MEMTOP
- .export MEMBOT
- .export SCNKEY
- .export SETTMO
- .export ACPTR
- .export CIOUT
- .export UNTLK
- .export UNLSN
- .export LISTEN
- .export TALK
- .export READST
- .export SETLFS
- .export SETNAM
- .export OPEN
- .export CLOSE
- .export CHKIN
- .export CKOUT
- .export CLRCH
- .export BASIN
- .export BSOUT
- .export LOAD
- .export SAVE
- .export SETTIM
- .export RDTIM
- .export STOP
- .export GETIN
- .export CLALL
- .export UDTIM
- .export SCREEN
- .export PLOT
- .export IOBASE
-
-
-;-----------------------------------------------------------------------------
-; All functions are available in the kernal jump table
-
-CINT = $FF81
-IOINIT = $FF84
-RAMTAS = $FF87
-RESTOR = $FF8A
-VECTOR = $FF8D
-SETMSG = $FF90
-SECOND = $FF93
-TKSA = $FF96
-MEMTOP = $FF99
-MEMBOT = $FF9C
-SCNKEY = $FF9F
-SETTMO = $FFA2
-ACPTR = $FFA5
-CIOUT = $FFA8
-UNTLK = $FFAB
-UNLSN = $FFAE
-LISTEN = $FFB1
-TALK = $FFB4
-READST = $FFB7
-SETLFS = $FFBA
-SETNAM = $FFBD
-OPEN = $FFC0
-CLOSE = $FFC3
-CHKIN = $FFC6
-CKOUT = $FFC9
-CLRCH = $FFCC
-BASIN = $FFCF
-BSOUT = $FFD2
-LOAD = $FFD5
-SAVE = $FFD8
-SETTIM = $FFDB
-RDTIM = $FFDE
-STOP = $FFE1
-GETIN = $FFE4
-CLALL = $FFE7
-UDTIM = $FFEA
-SCREEN = $FFED
-PLOT = $FFF0
-IOBASE = $FFF3
-
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; IOBASE replacement function
+;
+
+ .export IOBASE
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc IOBASE
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFF3 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; LISTEN replacement function
+;
+
+ .export LISTEN
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc LISTEN
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFB1 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; LOAD replacement function
+;
+
+ .export LOAD
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc LOAD
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFD5 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; OPEN replacement function
+;
+
+ .export OPEN
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc OPEN
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFC0 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; RDTIM replacement function
+;
+
+ .export RDTIM
+
+ .include "plus4.inc"
+
+; Read the clock from the zero page to avoid banking in the ROM
+
+.proc RDTIM
+ sei ; No interrupts
+ lda TIME+2
+ ldx TIME+1
+ ldy TIME ; Read the time
+ cli ; Allow interrupts
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; READST replacement function
+;
+
+ .export READST
+
+ .include "plus4.inc"
+
+; Read the status byte from the zero page instead of banking in the ROM
+
+.proc READST
+ lda ST ; Load status
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; SAVE replacement function
+;
+
+ .export SAVE
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc SAVE
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFD8 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; SETLFS replacement function
+;
+
+ .export SETLFS
+
+ .include "plus4.inc"
+
+; Write directly to the zero page to avoid banking in the ROM
+
+.proc SETLFS
+ sta LFN
+ stx DEVNUM
+ sty SECADR
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; SETNAM replacement function
+;
+
+ .export SETNAM
+
+ .include "plus4.inc"
+
+; This function is special in that the name must reside in low memory,
+; otherwise it is not accessible by the ROM code.
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc SETNAM
+
+; Limit the length of the name and store it into the zero page
+
+ cmp #16+1
+ bcc @L1
+ lda #16 ; Use a maximum of 16 chars
+@L1: sta FNAM_LEN
+
+; Check if we have to copy the name to low memory
+
+ cmp #$00 ; Length zero?
+ beq @L3 ; Yes: Copying not needed
+ cpy #$00 ; Is the name in low memory?
+ bpl @L3 ; Yes: Copying not needed
+
+; Store the length and the pointer to the name
+
+ stx TMPPTR
+ sty TMPPTR+1 ; Store pointer to name in TMPPTR
+
+; Copy the given name into DOS_FN1
+
+ ldy #$00
+@L2: lda (TMPPTR),y
+ sta DOS_FN1,y
+ iny
+ cpy FNAM_LEN
+ bne @L2
+
+; Load the new parameters for the low memory buffer
+
+ ldx #<DOS_FN1
+ ldy #>DOS_FN1
+
+; Instead of banking in the ROM, store the values directly into the zeropage
+
+@L3: stx FNAM_ADR
+ sty FNAM_ADR+1
+
+; Return to caller
+
+ rts
+
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; SETTIM replacement function
+;
+
+ .export SETTIM
+
+ .include "plus4.inc"
+
+; Set the clock by writing directly to zero page to avoid banking in the ROM
+
+.proc SETTIM
+ sei ; No interrupts
+ sta TIME+2
+ stx TIME+1
+ sty TIME ; Set the time
+ cli ; Allow interrupts
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; TALK replacement function
+;
+
+ .export TALK
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc TALK
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFB4 ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; UNLSN replacement function
+;
+
+ .export UNLSN
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc UNLSN
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFAE ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
--- /dev/null
+;
+; Ullrich von Bassewitz, 22.11.2002
+;
+; UNTLK replacement function
+;
+
+ .export UNTLK
+
+ .include "plus4.inc"
+
+.segment "LOWCODE" ; Must go into low memory
+
+.proc UNTLK
+ sta ENABLE_ROM ; Enable the ROM
+ jsr $FFAB ; Call the ROM routine
+ sta ENABLE_RAM ; Switch back to RAM
+ rts ; Return to caller
+.endproc
+
+
; ---------------------------------------------------------------------------
; Zero page, Commodore stuff
+TMPPTR = $22 ; Temporary ptr used by BASIC
ST = $90 ; IEC status byte
-
TIME = $A3 ; 60HZ clock
FNAM_LEN = $AB ; Length of filename
+LFN = $AC ; Logical file number
SECADR = $AD ; Secondary address
DEVNUM = $AE ; Device number
+FNAM_ADR = $AF ; Pointer to filename for OPEN
KEY_COUNT = $EF ; Number of keys in input buffer
CURS_X = $CA ; Cursor column
CURS_Y = $CD ; Cursor row
SCREEN_PTR = $C8 ; Pointer to current char in text screen
CRAM_PTR = $EA ; Pointer to current char in color RAM
+DOS_FN1 = $25E ; DOS filename buffer #1
+DOS_FN1LEN = $26E ; DOS filename length #1
CHARCOLOR = $53B
FKEY_COUNT = $55D ; Characters for function key
FKEY_SPACE = $55F ; Function key definitions
TED_ROMSEL = $FF3E
TED_RAMSEL = $FF3F
+; ---------------------------------------------------------------------------
+; RAM/ROM selection addresses
+
+ENABLE_ROM = $FF3E
+ENABLE_RAM = $FF3F
projects / cc65 / commitdiff