Add a preliminary external custom target for the Foenix F256 family of modern retro computers. (#171)

* flesh out C128-specific KERNAL calls

* fix: typo in comment

* fix: typo in comment

* fix: include return values of INDCMP

* fix: rearrange return values of INDCMP

README.md

@@ -96,7 +96,7 @@ What does Prog8 provide?
 - "c64": Commodore-64  (6502 like CPU)
 - "c128": Commodore-128  (6502 like CPU - the Z80 cpu mode is not supported)
 - "pet32": Commodore PET (limited support)
-- via external configurable targets: Atari 800 XL, Neo6502, NES, C64OS, ...
+- via external configurable targets: Atari 800 XL, Neo6502, NES, C64 OS, Foenix F256, ...
 - If you only use standard kernal and prog8 library routines, it is possible to compile the *exact same program* for different machines (just change the compiler target flag)
 
 

compiler/res/prog8lib/c128/syslib.p8

@@ -317,10 +317,25 @@ c128 {
     &ubyte  VM4     = $0A2F         ; starting page for VDC attribute mem
 
 
-; TODO c128 a bunch of kernal routines are missing here that are specific to the c128
-
-extsub $FF6E = JSRFAR()
-extsub $FF68 = SETBNK(ubyte databank @A, ubyte filenamebank @X)
+extsub $FF47 = SPIN_SPOUT() clobbers(A)                         ; set up serial bus for fast communications mode
+extsub $FF4A = CLOSE_ALL(ubyte device @X)  clobbers(X)          ; close all channels to specific device
+extsub $FF4D = C64_MODE()                                       ; restart machine in C64 mode (does not return)
+extsub $FF50 = DMA_CALL(ubyte bank @X, ubyte command @Y) clobbers(A,X) ; send a command to a DMA device
+extsub $FF53 = BOOT_CALL(ubyte device @X, ubyte drive @A) clobbers(A,X,Y) ; try to autoboot the given disk
+extsub $FF56 = PHOENIX() clobbers(A,X,Y)                        ; search for and autostart ROMs, cartridges, then default disk
+extsub $FF59 = LKUPLA(ubyte lfn @A) -> bool @Pc, ubyte @X       ; look up logical file number to see if it's open; returns device
+extsub $FF5C = LKUPSA(ubyte sa @Y) -> bool @Pc, ubyte @A, ubyte @X ; look up secondary address to see if it's in use; returns lfn and device
+extsub $FF5F = SWAPPER() clobbers(A,X,Y)                        ; swap active screen (between 40- and 80-column)
+extsub $FF62 = DLCHR() clobbers(A,X,Y)                          ; copy character ROM into VDC video RAM
+extsub $FF65 = PFKEY(ubyte zpaddr @A, ubyte key @X, ubyte length @Y) ; redefine programmable function key (string descriptor in zp, addr in A)
+extsub $FF68 = SETBNK(ubyte data_bank @A, ubyte filename_bank @X) ; set memory bank for load/save
+extsub $FF6B = GETCFG(ubyte bank @X) -> ubyte @A                ; translate bank number to MMU configuration register value
+extsub $FF6E = JSRFAR() clobbers(A,X)                           ; call routine in another bank (parameters set in zero page addresses 2-8)
+extsub $FF71 = JMPFAR() clobbers(A,X)                           ; jump without return to another bank (parameters set as for JSRFAR)
+extsub $FF74 = INDFET(ubyte zpaddr @A, ubyte bank @X, ubyte offset @Y) clobbers(X) -> ubyte @A ; fetch byte from another bank (address in zp, ptr in A)
+extsub $FF77 = INDSTA(ubyte value @A, ubyte bank @X, ubyte offset @Y) clobbers(X) ; store byte to another bank (address in zp, ptr in $02b9)
+extsub $FF7A = INDCMP(ubyte value @A, ubyte bank @X, ubyte offset @Y) clobbers(X) -> bool @Pz, bool @Pc, bool @Pv; compare byte in another bank (address in zp, ptr in $02c8)
+extsub $FF7D = PRIMM()                                          ; print immediate string
 
 
 ; ---- C128 specific system utility routines: ----

docs/source/_static/symboldumps/skeletons-c128.txt

@@ -494,8 +494,25 @@ c128  {
     &ubyte  VM2 
     &ubyte  VM3 
     &ubyte  VM4 
-    JSRFAR  ()  = $ff6e
-    SETBNK  (ubyte databank @A, ubyte filenamebank @X)  = $ff68
+    BOOT_CALL  (ubyte device @X, ubyte drive @A) -> clobbers (A,X,Y)  = $ff53
+    C64_MODE  ()  = $ff4d
+    CLOSE_ALL  (ubyte device @X) -> clobbers (X)  = $ff4a
+    DLCHR  () -> clobbers (A,X,Y)  = $ff62
+    DMA_CALL  (ubyte bank @X, ubyte command @Y) -> clobbers (A,X)  = $ff50
+    GETCFG  (ubyte bank @X) -> ubyte @A  = $ff6b
+    INDCMP  (ubyte value @A, ubyte bank @X, ubyte offset @Y) -> clobbers (X) -> bool @Pz, bool @Pc, bool @Pv  = $ff7a
+    INDFET  (ubyte zpaddr @A, ubyte bank @X, ubyte offset @Y) -> clobbers (X) -> ubyte @A  = $ff74
+    INDSTA  (ubyte value @A, ubyte bank @X, ubyte offset @Y) -> clobbers (X)  = $ff77
+    JMPFAR  () -> clobbers (A,X)  = $ff71
+    JSRFAR  () -> clobbers (A,X)  = $ff6e
+    LKUPLA  (ubyte lfn @A) -> bool @Pc, ubyte @X  = $ff59
+    LKUPSA  (ubyte sa @Y) -> bool @Pc, ubyte @A, ubyte @X  = $ff5c
+    PFKEY  (ubyte zpaddr @A, ubyte key @X, ubyte length @Y)  = $ff65
+    PHOENIX  () -> clobbers (A,X,Y)  = $ff56
+    PRIMM  ()  = $ff7d
+    SETBNK  (ubyte data_bank @A, ubyte filename_bank @X)  = $ff68
+    SPIN_SPOUT  () -> clobbers (A)  = $ff47
+    SWAPPER  () -> clobbers (A,X,Y)  = $ff5f
     banks  (ubyte banks @A) 
     disable_basic  () -> clobbers (A) 
     getbanks  () -> ubyte @A 

docs/source/index.rst

@@ -27,8 +27,8 @@ You can compile programs for various machines that are built in into the compile
 * Commodore 128 (limited support)
 * Commodore PET (limited support)
 * any other 65(C)02 target machine or setup can be configured to a great extent in a user written configuration file.
-  There are some examples included for the Atari 800 XL, NEO6502 and such.
-* some users have been experimenting with a NES and a C64OS target as well.
+  There are some examples included for the Atari 800 XL, NEO6502, Foenix F256, and such.
+* some users have been experimenting with a NES and a C64 OS target as well.
 
 Some language features are mentioned below, and you can also read :ref:`comparingprog8` if you
 want to quickly read about how Prog8 compares to well-known other languages.

docs/source/libraries.rst

@@ -1032,6 +1032,7 @@ sys (part of syslib)
     - 7 = Neo6502
     - 8 = Atari 8 bits
     - 16 = Commander X16
+    - 25 = Foenix F256 family
     - 64 = Commodore 64
     - 128 = Commodore 128
     - 255 = Virtual machine

docs/source/variables.rst

@@ -244,16 +244,9 @@ you have to make sure the resulting value fits into the byte or word size of the
 Booleans
 ^^^^^^^^
 
-Booleans are a distinct type in Prog8 and can have only the values ``true`` or ``false``.
-It can be casted to and from other integer types though
-where a nonzero integer is considered to be true, and zero is false.
-Logical expressions, comparisons and some other code tends to compile more efficiently if
-you explicitly use ``bool`` types instead of 0/1 integers.
-The in-memory representation of a boolean value is just a byte containing 0 or 1.
-
-If you find that you need a whole bunch of boolean variables or perhaps even an array of them,
-consider using integer bit mask variable + bitwise operators instead.
-This saves a lot of memory and may be faster as well.
+Booleans are a distinct type called ``bool`` in Prog8 and can have only the values ``true`` or ``false``.
+In memory, they are stored as a byte containing 0 or 1.
+You can cast any numeric to a bool, in which case 0 will become ``false`` and any nonzero value will become ``true``.
 
 
 Floating point numbers

examples/customtarget/Makefile

@@ -1,6 +1,6 @@
 .PHONY:  all clean
 
-all: main-c64.prg main-cx16.prg main-pet.prg atari-hello.xex atari-fibonacci.xex neo-hello.bin
+all: main-c64.prg main-cx16.prg main-pet.prg atari-hello.xex atari-fibonacci.xex neo-hello.bin f256-hello.bin
 
 clean:
 	rm -f *.prg *.PRG *.xex *.bin *.asm *.vice-*
@@ -26,6 +26,9 @@ atari-fibonacci.xex: src/atari-fibonacci.p8
 neo-hello.bin: src/neo-hello.p8
 	prog8c -target targetconfigs/neo6502.properties src/neo-hello.p8
 
+f256-hello.bin: src/f256-hello.p8
+	prog8c -target targetconfigs/f256.properties src/f256-hello.p8
+
 run-atari-hello:
 	prog8c -target targetconfigs/atari.properties src/atari-hello.p8 -emu
 

examples/customtarget/libraries/f256/syslib.p8

@@ -0,0 +1,907 @@
+; Prog8 definitions for the Foenix F256x
+
+%option no_symbol_prefixing, ignore_unused
+
+; compatiblity layer
+cbm {
+%option no_symbol_prefixing, ignore_unused
+
+    ; dumb hack to make some code compile.
+    ; TODO: figure out how the kernel clock works, not just
+    ; reading the RTC hardware
+    ubyte TIME_LO = $00
+
+    ;
+    ; Only reads keys right now.
+    ;
+    asmsub CHRIN() -> ubyte @A {
+        %asm {{
+-           stz f256.event.type         ; invalidate existing event type
+            jsr f256.event.NextEvent
+            lda f256.event.type
+            cmp #f256.event.key.PRESSED
+            bne -
+            lda f256.event.key.ascii    ; return upper or lower ASCII
+            rts
+        }}
+}
+
+    ; I though the alias was working but it isn't.
+    ;alias CHROUT = f256.chrout
+    asmsub CHROUT(ubyte character @ A) {
+        %asm {{
+            jmp f256.chrout
+        }}
+    }
+
+    ; TODO: set carry properly?
+    ; TODO: on CBM any device other than keyboard or RS-232 should jump to CHRIN
+    asmsub GETIN() -> bool @Pc, ubyte @A {
+        %asm {{
+-           stz f256.event.type         ; invalidate previous event type
+            lda f256.event.pending      ; return zero if no pending event
+            cmp #$ff                    ; $ff == no events pending
+            beq +                       ; done.
+            jsr f256.event.NextEvent
+            lda f256.event.type
+            cmp #f256.event.key.PRESSED
+            bne -
+            ;lda f256.event.key.raw     ; return key id / scan code? (case issue?)
+            lda f256.event.key.ascii    ; return upper or lower ASCII
+            clc                         ; clear carry when returning character
+            rts                         ; return ascii key
++           sec                         ; set carry when no character returned
+            lda #0                      ; return zero if no key
+            rts
+    }}
+}
+
+
+    asmsub GETINx() -> bool @Pc, ubyte @A {
+        %asm {{
+            rts
+        }}
+    }
+}
+
+f256 {
+%option no_symbol_prefixing, ignore_unused, force_output
+    ;
+    ; Foenix F256 hardware definitions
+    ;
+
+    ; MMU controls
+    &ubyte mem_ctrl     = $0000
+    &ubyte io_ctrl      = $0001
+
+    ; text screen size
+    const ubyte DEFAULT_WIDTH = 80
+    const ubyte DEFAULT_HEIGHT = 60
+
+    ; screen / color memory
+    const uword Colors  = $C000 ; IO page 2
+    const uword Screen  = $C000 ; IO page 3
+
+    ; self tracked screen coordinates
+    ; potentially could be at $04/$05 in reserved ZP area?
+    ubyte screen_row = 0
+    ubyte screen_col = 0
+    ubyte screen_color = $f2    ; default text/background color
+    &uword screen_ptr = $02 ; and $03.  used to calculate screen/color ram offsets
+
+    ;
+    ; calculates screen memory pointer for the start of a row
+    ; in screen_ptr in zeropage.
+    ; ldy column
+    ; sta (screen_ptr), y
+    ;
+    asmsub rowptr(ubyte row @Y) {
+        %asm {{
+            stz screen_ptr      ; reset to start of screen ram
+            lda #>f256.Screen
+            sta screen_ptr+1
+            cpy #0      ; row in @Y will be our loop counter
+            beq ptr_done
+    rowloop:
+            clc
+            lda screen_ptr      ; load count
+            adc #DEFAULT_WIDTH
+            bcc +
+            inc screen_ptr+1
+    +       sta screen_ptr
+            dey
+            bne rowloop
+    ptr_done:
+            rts
+        }}
+    }
+
+    ;
+    ; calculates screen memory pointer for the specific col/row
+    ; in screen_ptr in zeropage. Points directly to character after.
+    ; ldy #0
+    ; sta (screen_ptr), y
+    ;
+    asmsub chrptr(ubyte col @X, ubyte row @Y) clobbers(A) {
+        %asm {{
+            phx             ; preserve col
+            jsr  rowptr     ; calculate pointer to row
+            pla             ; restore col
+            clc
+            adc  screen_ptr
+            sta  screen_ptr 
+            bcc  +
+            inc  screen_ptr+1
+    +       rts
+        }}
+    }
+
+    asmsub chrout(ubyte character @ A) {
+        %asm {{
+            phx                     ; preserve x
+            phy                     ; preserve y
+            cmp #$0d                ; check for carriage return
+            beq crlf
+            cmp #$0a                ; check for line feed
+            beq crlf
+            pha                     ; preserve a
+            ldy screen_row
+            jsr rowptr              ; calculates screen pointer to start of row
+            ldy screen_col      ; column will be our index against the row pointer
+            lda #2
+            sta f256.io_ctrl        ; map in screen memory
+            pla
+            sta (screen_ptr),y
+            lda #3
+            sta f256.io_ctrl        ; map in color memory
+            lda screen_color
+            sta (screen_ptr),y
+            lda #0
+            sta f256.io_ctrl        ; return to default map
+            inc screen_col
+            lda screen_col
+            cmp #DEFAULT_WIDTH
+            bcc +                   ; less than DEFAULT_WIDTH
+    crlf:
+            stz screen_col
+            inc screen_row
+            lda screen_row
+            cmp #DEFAULT_HEIGHT
+            bcc +
+            sec
+            jsr scroll_up
+            dec screen_row
+    +       ply
+            plx
+            rts
+        }}
+    }
+
+    ;
+    ; implement here so chrout can work without importing textio.
+    ;
+    asmsub  scroll_up  (bool alsocolors @ Pc) clobbers(A,X)  {
+        ; ---- scroll the whole screen 1 character up
+        ;      contents of the bottom row are unchanged, you should refill/clear this yourself
+        ;      Carry flag determines if screen color data must be scrolled too
+        %asm {{
+            bcc  _scroll_screen
+
+    +               ; scroll the screen and the color memory
+            ldx #DEFAULT_WIDTH-1
+    -
+            lda #2
+            sta f256.io_ctrl        ; map in screen memory
+            .for row=1, row<=DEFAULT_HEIGHT, row+=1
+                lda  f256.Screen + DEFAULT_WIDTH*row,x
+                sta  f256.Screen + DEFAULT_WIDTH*(row-1),x
+            .next
+            lda #3
+            sta f256.io_ctrl        ; map in color memory
+            .for row=1, row<=DEFAULT_HEIGHT, row+=1
+                lda  f256.Colors + DEFAULT_WIDTH*row,x
+                sta  f256.Colors + DEFAULT_WIDTH*(row-1),x
+            .next
+
+
+            dex
+            bpl  -
+            lda #0
+            sta f256.io_ctrl        ; restore I/O configuration
+            rts
+
+    _scroll_screen  ; scroll only the screen memory
+            ldx #DEFAULT_WIDTH-1
+    -
+            lda #2
+            sta f256.io_ctrl        ; map in screen memory
+            .for row=1, row<=DEFAULT_HEIGHT, row+=1
+                lda  f256.Screen + DEFAULT_WIDTH*row,x
+                sta  f256.Screen + DEFAULT_WIDTH*(row-1),x
+            .next
+            dex
+            bpl  -
+            lda #0
+            sta f256.io_ctrl        ; restore I/O configuration
+            rts
+        }}
+    }
+
+    ; args
+    sub args() {
+        &uword ext        = $00f8
+        &ubyte extlen     = $00fa
+        &uword buf        = $00fb
+        &ubyte buflen     = $00fd
+        &uword ptr        = $00fe
+    }
+
+    ; kernel event calls & event types
+    sub event() {
+        &uword dest             = $00f0
+        &ubyte pending          = $00f2
+        &ubyte[8] packet        = $00e8   ; 8-byte buffer in ZP for kernel events.
+
+        ; event buffer fields
+        &ubyte type             = &packet   ; event type (definitions below)
+        &ubyte buf              = &packet+1 ; page id or zero
+        &ubyte ext              = &packet+2 ; page id or zero
+
+        ; kernel event calls
+        extsub $ff00 = NextEvent()  ; Copy next event to application buffer.
+        extsub $ff04 = ReadData()   ; Copy primary bulk event data to application.
+        extsub $ff08 = ReadExt()    ; Copy secondary bulk event data to application.
+
+        sub init() {
+            f256.event.dest = &f256.event.packet
+        }
+
+        ; event type definitions
+        const uword reserved        = $00 ; $01
+        const uword deprecated      = $02 ; $03
+        const uword JOYSTICK        = $04 ; $05 ; game controller changes
+        const uword DEVICE          = $06 ; $07 ; device added or removed
+        sub key() {
+            const uword PRESSED     = $08 ; $09
+            const uword RELEASED    = $0a ; $0b
+            &ubyte keyboard         = &packet+3 ; keyboard id
+            &ubyte raw              = &packet+4 ; raw key id/code
+            &ubyte ascii            = &packet+5 ; ASCII value
+            &ubyte flags            = &packet+6 ; flag (META)
+            const ubyte META        = $80       ; meta key no ASCII value
+        }
+        sub mouse() {
+            const uword DELTA       = $0c ; $0d
+            const uword CLICKS      = $0e ; $0f
+        }
+        sub block() {
+            const uword NAME        = $10 ; $11
+            const uword SIZE        = $12 ; $13
+            const uword DATA        = $14 ; $15 ; read request succeeded
+            const uword WROTE       = $16 ; $17 ; write request completed
+            const uword FORMATTED   = $18 ; $19 ; low-level format completed
+            const uword ERROR       = $1a ; $1b
+        }
+        sub fs() {
+            const uword SIZE        = $1c ; $1d
+            const uword CREATED     = $1e ; $1f
+            const uword CHECKED     = $20 ; $21
+            const uword DATA        = $22 ; $23 ; read request succeeded
+            const uword WROTE       = $24 ; $25 ; write request completed
+            const uword ERROR       = $26 ; $27
+        }
+        sub file() {
+            const uword NOT_FOUND   = $28 ; $29 ; file was not found
+            const uword OPENED      = $2a ; $2b ; file successfully opened
+            const uword DATA        = $2c ; $2d ; read request succeeded
+            const uword WROTE       = $2e ; $2f ; write request completed
+            const uword EOF         = $30 ; $31 ; all file data has been read
+            const uword CLOSED      = $32 ; $33 ; close request completed
+            const uword RENAMED     = $34 ; $35 ; renamed request completed
+            const uword DELETED     = $36 ; $37 ; delete request completed
+            const uword ERROR       = $38 ; $39 ; error occurred, close file if opened
+            const uword SEEK        = $3a ; $3b ; seek request completed
+        }
+        sub directory() {
+            const uword OPENED      = $3c ; $3d ; directory open succeeded
+            const uword VOLUME      = $3e ; $3f ; volume record found
+            const uword FILE        = $40 ; $41 ; file record found
+            const uword FREE        = $42 ; $43 ; file-system free-space record found
+            const uword EOF         = $44 ; $45 ; all data read
+            const uword CLOSED      = $46 ; $47 ; directory file closed
+            const uword ERROR       = $48 ; $49 ; error occurred, close if opened
+            const uword CREATED     = $4a ; $4b ; directory created
+            const uword DELETED     = $4a ; $4b ; directory deleted
+        }
+        sub net() {
+            const uword TCP         = $4c ; $4d
+            const uword UDP         = $4e ; $4f
+        }
+        sub timer() {
+            const uword EXPIRED     = $50 ; $51
+        }
+        sub clock() {
+            const uword TICK        = $52 ; $53
+        }
+        sub irq() {
+            const uword IRQ         = $54 ; $55
+        }
+    }
+
+    ; kernel display calls
+    sub display() {
+        &ubyte x          = $00f3
+        &ubyte y          = $00f4
+        &uword color      = &f256.args.ext
+        &uword text       = &f256.args.buf
+        &ubyte buflen     = &f256.args.buflen
+        const uword GetSize_    = $ffd0     ; Get screen dimensions
+        const uword DrawRow_    = $ffd4     ; Draw text/color buffers left-to-right
+        const uword DrawColumn_ = $ffd8     ; Draw text/color buffers top-to-bottom
+    }
+
+
+
+    ;
+    &uword  NMI_VEC   = $FFFA  ; 6502 nmi vector
+    &uword  RESET_VEC = $FFFC  ; 6502 reset vector
+    &uword  IRQ_VEC   = $FFFE  ; 6502 interrupt vector
+
+    ;%asminclude "api.asm"
+}
+
+sys {
+    ; ------- lowlevel system routines --------
+
+    const ubyte target = 25         ;  compilation target specifier.  255=virtual, 128=C128, 64=C64, 32=PET, 25=Foenix F256, 16=CommanderX16, 8=atari800XL, 7=Neo6502
+
+    const ubyte SIZEOF_BOOL  = sizeof(bool)
+    const ubyte SIZEOF_BYTE  = sizeof(byte)
+    const ubyte SIZEOF_UBYTE = sizeof(ubyte)
+    const ubyte SIZEOF_WORD  = sizeof(word)
+    const ubyte SIZEOF_UWORD = sizeof(uword)
+    const ubyte SIZEOF_LONG  = sizeof(long)
+;    const ubyte SIZEOF_POINTER = sizeof(&sys.wait)
+    const ubyte SIZEOF_FLOAT = 0    ; undefined, no floats supported
+    const byte  MIN_BYTE     = -128
+    const byte  MAX_BYTE     = 127
+    const ubyte MIN_UBYTE    = 0
+    const ubyte MAX_UBYTE    = 255
+    const word  MIN_WORD     = -32768
+    const word  MAX_WORD     = 32767
+    const uword MIN_UWORD    = 0
+    const uword MAX_UWORD    = 65535
+    ; MIN_FLOAT and MAX_FLOAT are defined in the floats module if importec
+
+
+    asmsub  reset_system()  {
+        ; Soft-reset the system back to initial power-on status
+        ; TODO
+        %asm {{
+            sei
+            jmp  (f256.RESET_VEC)
+        }}
+    }
+
+    sub wait(uword jiffies) {
+        ; --- wait approximately the given number of jiffies (1/60th seconds)
+        ;     TODO
+    }
+
+    asmsub waitvsync() clobbers(A) {
+        ; --- busy wait till the next vsync has occurred (approximately), without depending on custom irq handling.
+        ;     TODO
+        %asm {{
+            nop
+            rts
+        }}
+    }
+
+    asmsub internal_stringcopy(uword source @R0, uword target @AY) clobbers (A,Y) {
+        ; Called when the compiler wants to assign a string value to another string.
+        %asm {{
+		sta  P8ZP_SCRATCH_W1
+		sty  P8ZP_SCRATCH_W1+1
+		lda  cx16.r0
+		ldy  cx16.r0+1
+		jmp  prog8_lib.strcpy
+        }}
+    }
+
+    asmsub memcopy(uword source @R0, uword target @R1, uword count @AY) clobbers(A,X,Y) {
+        ; note: only works for NON-OVERLAPPING memory regions!
+        ; note: can't be inlined because is called from asm as well
+        %asm {{
+            ldx  cx16.r0
+            stx  P8ZP_SCRATCH_W1        ; source in ZP
+            ldx  cx16.r0+1
+            stx  P8ZP_SCRATCH_W1+1
+            ldx  cx16.r1
+            stx  P8ZP_SCRATCH_W2        ; target in ZP
+            ldx  cx16.r1+1
+            stx  P8ZP_SCRATCH_W2+1
+            cpy  #0
+            bne  _longcopy
+
+            ; copy <= 255 bytes
+            tay
+            bne  _copyshort
+            rts     ; nothing to copy
+
+_copyshort
+            dey
+            beq  +
+-           lda  (P8ZP_SCRATCH_W1),y
+            sta  (P8ZP_SCRATCH_W2),y
+            dey
+            bne  -
++           lda  (P8ZP_SCRATCH_W1),y
+            sta  (P8ZP_SCRATCH_W2),y
+            rts
+
+_longcopy
+            sta  P8ZP_SCRATCH_B1        ; lsb(count) = remainder in last page
+            tya
+            tax                         ; x = num pages (1+)
+            ldy  #0
+-           lda  (P8ZP_SCRATCH_W1),y
+            sta  (P8ZP_SCRATCH_W2),y
+            iny
+            bne  -
+            inc  P8ZP_SCRATCH_W1+1
+            inc  P8ZP_SCRATCH_W2+1
+            dex
+            bne  -
+            ldy  P8ZP_SCRATCH_B1
+            bne  _copyshort
+            rts
+        }}
+    }
+
+    asmsub memset(uword mem @R0, uword numbytes @R1, ubyte value @A) clobbers(A,X,Y) {
+        %asm {{
+            ldy  cx16.r0
+            sty  P8ZP_SCRATCH_W1
+            ldy  cx16.r0+1
+            sty  P8ZP_SCRATCH_W1+1
+            ldx  cx16.r1
+            ldy  cx16.r1+1
+            jmp  prog8_lib.memset
+        }}
+    }
+
+    asmsub memsetw(uword mem @R0, uword numwords @R1, uword value @AY) clobbers(A,X,Y) {
+        %asm {{
+            ldx  cx16.r0
+            stx  P8ZP_SCRATCH_W1
+            ldx  cx16.r0+1
+            stx  P8ZP_SCRATCH_W1+1
+            ldx  cx16.r1
+            stx  P8ZP_SCRATCH_W2
+            ldx  cx16.r1+1
+            stx  P8ZP_SCRATCH_W2+1
+            jmp  prog8_lib.memsetw
+        }}
+    }
+
+    inline asmsub read_flags() -> ubyte @A {
+        %asm {{
+        php
+        pla
+        }}
+    }
+
+    inline asmsub clear_carry() {
+        %asm {{
+        clc
+        }}
+    }
+
+    inline asmsub set_carry() {
+        %asm {{
+        sec
+        }}
+    }
+
+    inline asmsub clear_irqd() {
+        %asm {{
+        cli
+        }}
+    }
+
+    inline asmsub set_irqd() {
+        %asm {{
+        sei
+        }}
+    }
+
+    inline asmsub irqsafe_set_irqd() {
+        %asm {{
+        php
+        sei
+        }}
+    }
+
+    inline asmsub irqsafe_clear_irqd() {
+        %asm {{
+        plp
+        }}
+    }
+
+    sub disable_caseswitch() {
+        ; no-op
+    }
+
+    sub enable_caseswitch() {
+        ; no-op
+    }
+
+    asmsub save_prog8_internals() {
+        %asm {{
+            lda  P8ZP_SCRATCH_B1
+            sta  save_SCRATCH_ZPB1
+            lda  P8ZP_SCRATCH_REG
+            sta  save_SCRATCH_ZPREG
+            lda  P8ZP_SCRATCH_W1
+            sta  save_SCRATCH_ZPWORD1
+            lda  P8ZP_SCRATCH_W1+1
+            sta  save_SCRATCH_ZPWORD1+1
+            lda  P8ZP_SCRATCH_W2
+            sta  save_SCRATCH_ZPWORD2
+            lda  P8ZP_SCRATCH_W2+1
+            sta  save_SCRATCH_ZPWORD2+1
+            rts
+            .section BSS
+save_SCRATCH_ZPB1	.byte  ?
+save_SCRATCH_ZPREG	.byte  ?
+save_SCRATCH_ZPWORD1	.word  ?
+save_SCRATCH_ZPWORD2	.word  ?
+            .send BSS
+            ; !notreached!
+        }}
+    }
+
+    asmsub restore_prog8_internals() {
+        %asm {{
+            lda  save_prog8_internals.save_SCRATCH_ZPB1
+            sta  P8ZP_SCRATCH_B1
+            lda  save_prog8_internals.save_SCRATCH_ZPREG
+            sta  P8ZP_SCRATCH_REG
+            lda  save_prog8_internals.save_SCRATCH_ZPWORD1
+            sta  P8ZP_SCRATCH_W1
+            lda  save_prog8_internals.save_SCRATCH_ZPWORD1+1
+            sta  P8ZP_SCRATCH_W1+1
+            lda  save_prog8_internals.save_SCRATCH_ZPWORD2
+            sta  P8ZP_SCRATCH_W2
+            lda  save_prog8_internals.save_SCRATCH_ZPWORD2+1
+            sta  P8ZP_SCRATCH_W2+1
+            rts
+        }}
+    }
+
+    asmsub exit(ubyte returnvalue @A) {
+        ; -- immediately exit the program with a return code in the A register
+        %asm {{
+            sta  p8_sys_startup.cleanup_at_exit._exitcode
+            ldx  prog8_lib.orig_stackpointer
+            txs
+            jmp  p8_sys_startup.cleanup_at_exit
+        }}
+    }
+
+    asmsub exit2(ubyte resulta @A, ubyte resultx @X, ubyte resulty @Y) {
+        ; -- immediately exit the program with result values in the A, X and Y registers.
+        %asm {{
+            sta  p8_sys_startup.cleanup_at_exit._exitcode
+            stx  p8_sys_startup.cleanup_at_exit._exitcodeX
+            sty  p8_sys_startup.cleanup_at_exit._exitcodeY
+            ldx  prog8_lib.orig_stackpointer
+            txs
+            jmp  p8_sys_startup.cleanup_at_exit
+        }}
+    }
+
+    asmsub exit3(ubyte resulta @A, ubyte resultx @X, ubyte resulty @Y, bool carry @Pc) {
+        ; -- immediately exit the program with result values in the A, X and Y registers, and the Carry flag in the status register.
+        %asm {{
+            sta  p8_sys_startup.cleanup_at_exit._exitcode
+            lda  #0
+            rol  a
+            sta  p8_sys_startup.cleanup_at_exit._exitcarry
+            stx  p8_sys_startup.cleanup_at_exit._exitcodeX
+            sty  p8_sys_startup.cleanup_at_exit._exitcodeY
+            ldx  prog8_lib.orig_stackpointer
+            txs
+            jmp  p8_sys_startup.cleanup_at_exit
+        }}
+    }
+
+    inline asmsub progend() -> uword @AY {
+        %asm {{
+            lda  #<prog8_program_end
+            ldy  #>prog8_program_end
+        }}
+    }
+
+    inline asmsub progstart() -> uword @AY {
+        %asm {{
+            lda  #<prog8_program_start
+            ldy  #>prog8_program_start
+        }}
+    }
+
+    inline asmsub push(ubyte value @A) {
+        %asm {{
+            pha
+        }}
+    }
+
+    inline asmsub pushw(uword value @AY) {
+        %asm {{
+            pha
+            tya
+            pha
+        }}
+    }
+
+    inline asmsub push_returnaddress(uword address @XY) {
+        %asm {{
+            ; push like JSR would:  address-1,  MSB first then LSB
+            cpx  #0
+            bne  +
+            dey
++           dex
+            tya
+            pha
+            txa
+            pha
+        }}
+    }
+
+    inline asmsub pop() -> ubyte @A {
+        %asm {{
+            pla
+        }}
+    }
+
+    inline asmsub popw() -> uword @AY {
+        %asm {{
+            pla
+            tay
+            pla
+        }}
+    }
+
+}
+
+cx16 {
+; the sixteen virtual 16-bit registers in both normal unsigned mode and signed mode (s)
+    &uword r0  = $0010
+    &uword r1  = $0012
+    &uword r2  = $0014
+    &uword r3  = $0016
+    &uword r4  = $0018
+    &uword r5  = $001a
+    &uword r6  = $001c
+    &uword r7  = $001e
+    &uword r8  = $0020
+    &uword r9  = $0022
+    &uword r10 = $0024
+    &uword r11 = $0026
+    &uword r12 = $0028
+    &uword r13 = $002a
+    &uword r14 = $002c
+    &uword r15 = $002e
+
+    ; signed word versions
+    &word r0s  = $0010
+    &word r1s  = $0012
+    &word r2s  = $0014
+    &word r3s  = $0016
+    &word r4s  = $0018
+    &word r5s  = $001a
+    &word r6s  = $001c
+    &word r7s  = $001e
+    &word r8s  = $0020
+    &word r9s  = $0022
+    &word r10s = $0024
+    &word r11s = $0026
+    &word r12s = $0028
+    &word r13s = $002a
+    &word r14s = $002c
+    &word r15s = $002e
+
+    ; ubyte versions (low and high bytes)
+    &ubyte r0L  = $0010
+    &ubyte r1L  = $0012
+    &ubyte r2L  = $0014
+    &ubyte r3L  = $0016
+    &ubyte r4L  = $0018
+    &ubyte r5L  = $001a
+    &ubyte r6L  = $001c
+    &ubyte r7L  = $001e
+    &ubyte r8L  = $0020
+    &ubyte r9L  = $0022
+    &ubyte r10L = $0024
+    &ubyte r11L = $0026
+    &ubyte r12L = $0028
+    &ubyte r13L = $002a
+    &ubyte r14L = $002c
+    &ubyte r15L = $002e
+
+    &ubyte r0H  = $0011
+    &ubyte r1H  = $0013
+    &ubyte r2H  = $0015
+    &ubyte r3H  = $0017
+    &ubyte r4H  = $0019
+    &ubyte r5H  = $001b
+    &ubyte r6H  = $001d
+    &ubyte r7H  = $001f
+    &ubyte r8H  = $0021
+    &ubyte r9H  = $0023
+    &ubyte r10H = $0025
+    &ubyte r11H = $0027
+    &ubyte r12H = $0029
+    &ubyte r13H = $002b
+    &ubyte r14H = $002d
+    &ubyte r15H = $002f
+
+    ; signed byte versions (low and high bytes)
+    &byte r0sL  = $0010
+    &byte r1sL  = $0012
+    &byte r2sL  = $0014
+    &byte r3sL  = $0016
+    &byte r4sL  = $0018
+    &byte r5sL  = $001a
+    &byte r6sL  = $001c
+    &byte r7sL  = $001e
+    &byte r8sL  = $0020
+    &byte r9sL  = $0022
+    &byte r10sL = $0024
+    &byte r11sL = $0026
+    &byte r12sL = $0028
+    &byte r13sL = $002a
+    &byte r14sL = $002c
+    &byte r15sL = $002e
+
+    &byte r0sH  = $0011
+    &byte r1sH  = $0013
+    &byte r2sH  = $0015
+    &byte r3sH  = $0017
+    &byte r4sH  = $0019
+    &byte r5sH  = $001b
+    &byte r6sH  = $001d
+    &byte r7sH  = $001f
+    &byte r8sH  = $0021
+    &byte r9sH  = $0023
+    &byte r10sH = $0025
+    &byte r11sH = $0027
+    &byte r12sH = $0029
+    &byte r13sH = $002b
+    &byte r14sH = $002d
+    &byte r15sH = $002f
+
+    ; boolean versions
+    &bool r0bL  = $0010
+    &bool r1bL  = $0012
+    &bool r2bL  = $0014
+    &bool r3bL  = $0016
+    &bool r4bL  = $0018
+    &bool r5bL  = $001a
+    &bool r6bL  = $001c
+    &bool r7bL  = $001e
+    &bool r8bL  = $0020
+    &bool r9bL  = $0022
+    &bool r10bL = $0024
+    &bool r11bL = $0026
+    &bool r12bL = $0028
+    &bool r13bL = $002a
+    &bool r14bL = $002c
+    &bool r15bL = $002e
+
+    &bool r0bH  = $0011
+    &bool r1bH  = $0013
+    &bool r2bH  = $0015
+    &bool r3bH  = $0017
+    &bool r4bH  = $0019
+    &bool r5bH  = $001b
+    &bool r6bH  = $001d
+    &bool r7bH  = $001f
+    &bool r8bH  = $0021
+    &bool r9bH  = $0023
+    &bool r10bH = $0025
+    &bool r11bH = $0027
+    &bool r12bH = $0029
+    &bool r13bH = $002b
+    &bool r14bH = $002d
+    &bool r15bH = $002f
+
+
+    asmsub save_virtual_registers() clobbers(A,Y) {
+        %asm {{
+            ldy  #31
+    -       lda  cx16.r0,y
+            sta  _cx16_vreg_storage,y
+            dey
+            bpl  -
+            rts
+
+            .section BSS
+    _cx16_vreg_storage
+            .word ?,?,?,?,?,?,?,?
+            .word ?,?,?,?,?,?,?,?
+            .send BSS
+            ; !notreached!
+        }}
+    }
+
+    asmsub restore_virtual_registers() clobbers(A,Y) {
+        %asm {{
+            ldy  #31
+    -       lda  save_virtual_registers._cx16_vreg_storage,y
+            sta  cx16.r0,y
+            dey
+            bpl  -
+            rts
+        }}
+    }
+
+    sub cpu_is_65816() -> bool {
+        ; Returns true when you have a 65816 cpu, false when it's a 6502.
+        return false
+    }
+
+}
+
+p8_sys_startup {
+    ; program startup and shutdown machinery. Needs to reside in normal system ram.
+
+    asmsub  init_system()  {
+        ; Initializes the machine to a sane starting state.
+        ; Called automatically by the loader program logic.
+        %asm {{
+            sei
+            cld
+            clc
+            ; TODO reset screen mode etc etc?
+            clv
+            ; TODO what about IRQ handler?
+            cli
+            rts
+        }}
+    }
+
+    asmsub  init_system_phase2()  {
+        %asm {{
+            ; initialize kernel event interface
+            lda  #<f256.event.packet
+            sta  f256.event.dest+0
+            stz  f256.event.dest+1
+            ;sta  f256.args.ext+0   ; check cc65 crt0.s for setup?
+            ;stz  f256.args.ext+1
+            rts
+        }}
+    }
+
+    asmsub  cleanup_at_exit() {
+        ; executed when the main subroutine does rts
+        %asm {{
+            lda  _exitcarry
+            lsr  a
+            lda  _exitcode
+            ldx  _exitcodeX
+            ldy  _exitcodeY
+            rts
+
+            .section BSS
+_exitcarry  .byte ?
+_exitcode   .byte ?
+_exitcodeX  .byte ?
+_exitcodeY  .byte ?
+            .send BSS
+
+            ; !notreached!
+        }}
+    }
+
+}

examples/customtarget/libraries/f256/textio.p8

@@ -0,0 +1,446 @@
+; Prog8 definitions for the Text I/O and Screen routines for the Foenix F256
+;
+
+%import syslib
+%import conv
+%import shared_cbm_textio_functions
+
+txt {
+%option no_symbol_prefixing, ignore_unused
+
+    ;alias chrout = f256.chrout
+    asmsub chrout(ubyte character @A) {
+        %asm {{
+            jmp  f256.chrout
+        }}
+    }
+
+    ; text screen size
+    const ubyte DEFAULT_WIDTH = f256.DEFAULT_WIDTH
+    const ubyte DEFAULT_HEIGHT = f256.DEFAULT_HEIGHT
+
+
+sub  clear_screen() {
+    fill_screen(' ', f256.screen_color)
+    f256.screen_col = 0
+    f256.screen_row = 0
+}
+
+sub  cls() {
+    clear_screen()
+}
+
+sub home() {
+    f256.screen_row = 0
+    f256.screen_col = 0
+}
+
+sub nl() {
+    f256.chrout($0d)
+    ;f256.chrout($0a)
+}
+
+sub spc() {
+    f256.chrout(' ')
+}
+
+sub bell() {
+    ; beep
+;    c64.MVOL = 11
+;    c64.AD1 = %00110111
+;    c64.SR1 = %00000000
+;    c64.FREQ1 = 8500
+;    c64.CR1 = %00010000
+;    c64.CR1 = %00010001
+}
+
+asmsub column(ubyte col @A) clobbers(A, X, Y) {
+    ; ---- set the cursor on the given column (starting with 0) on the current line
+    %asm {{
+        sta f256.screen_col
+        rts
+    }}
+}
+
+
+asmsub get_column() -> ubyte @Y {
+    %asm {{
+        ldy f256.screen_col
+        rts
+    }}
+}
+
+asmsub row(ubyte rownum @A) clobbers(A, X, Y) {
+    ; ---- set the cursor on the given row (starting with 0) on the current line
+    %asm {{
+        sta f256.screen_row
+        rts
+    }}
+}
+
+asmsub get_row() -> ubyte @X {
+    %asm {{
+        ldx f256.screen_row
+        rts
+    }}
+}
+
+asmsub get_cursor() -> ubyte @X, ubyte @Y {
+    %asm {{
+        ldx f256.screen_row
+        ldy f256.screen_col
+        rts
+    }}
+}
+
+asmsub  fill_screen (ubyte character @ A, ubyte color @ Y) clobbers(A)  {
+    ; ---- fill the character screen with the given fill character and character color.
+    ;      (assumes screen and color matrix are at their default addresses)
+
+    %asm {{
+        pha
+        tya
+        jsr  clear_screencolors
+        pla
+        jsr  clear_screenchars
+        rts
+        }}
+}
+
+asmsub  clear_screenchars (ubyte character @ A) clobbers(Y)  {
+    ; ---- clear the character screen with the given fill character (leaves colors)
+    ;      (assumes screen matrix is at the default address)
+    %asm {{
+        ldy  f256.io_ctrl           ; load current mapping
+        phy                         ; save to stack
+        ldy  #2
+        sty  f256.io_ctrl           ; map in screen memory
+        ldy  #240
+-       sta  f256.Screen+240*0-1,y
+        sta  f256.Screen+240*1-1,y
+        sta  f256.Screen+240*2-1,y
+        sta  f256.Screen+240*3-1,y
+        sta  f256.Screen+240*4-1,y
+        sta  f256.Screen+240*5-1,y
+        sta  f256.Screen+240*6-1,y
+        sta  f256.Screen+240*7-1,y
+        sta  f256.Screen+240*8-1,y
+        sta  f256.Screen+240*9-1,y
+        sta  f256.Screen+240*10-1,y
+        sta  f256.Screen+240*11-1,y
+        sta  f256.Screen+240*12-1,y
+        sta  f256.Screen+240*13-1,y
+        sta  f256.Screen+240*14-1,y
+        sta  f256.Screen+240*15-1,y
+        sta  f256.Screen+240*16-1,y
+        sta  f256.Screen+240*17-1,y
+        sta  f256.Screen+240*18-1,y
+        sta  f256.Screen+240*19-1,y
+        dey
+        bne  -
+        ply                         ; previous mapping from stack
+        sty  f256.io_ctrl           ; restore previous map
+        rts
+        }}
+}
+
+asmsub  clear_screencolors (ubyte color @ A) clobbers(Y)  {
+    ; ---- clear the character screen colors with the given color (leaves characters).
+    ;      (assumes color matrix is at the default address)
+    %asm {{
+        ldy  f256.io_ctrl           ; load current mapping
+        phy                         ; save to stack
+        ldy  #3
+        sty  f256.io_ctrl           ; map in color memory
+        ldy  #240
+-       sta  f256.Colors+240*0-1,y
+        sta  f256.Colors+240*1-1,y
+        sta  f256.Colors+240*2-1,y
+        sta  f256.Colors+240*3-1,y
+        sta  f256.Colors+240*4-1,y
+        sta  f256.Colors+240*5-1,y
+        sta  f256.Colors+240*6-1,y
+        sta  f256.Colors+240*7-1,y
+        sta  f256.Colors+240*8-1,y
+        sta  f256.Colors+240*9-1,y
+        sta  f256.Colors+240*10-1,y
+        sta  f256.Colors+240*11-1,y
+        sta  f256.Colors+240*12-1,y
+        sta  f256.Colors+240*13-1,y
+        sta  f256.Colors+240*14-1,y
+        sta  f256.Colors+240*15-1,y
+        sta  f256.Colors+240*16-1,y
+        sta  f256.Colors+240*17-1,y
+        sta  f256.Colors+240*18-1,y
+        sta  f256.Colors+240*19-1,y
+        dey
+        bne  -
+        ply                         ; previous mapping from stack
+        sty  f256.io_ctrl           ; restore previous map
+        rts
+        }}
+}
+
+sub color (ubyte txtcol) {
+    f256.screen_color = txtcol
+}
+
+sub lowercase() {
+;    c64.VMCSB |= 2
+}
+
+sub uppercase() {
+;    c64.VMCSB &= ~2
+}
+
+asmsub  scroll_left  (bool alsocolors @ Pc) clobbers(A, X, Y)  {
+    ; ---- scroll the whole screen 1 character to the left
+    ;      contents of the rightmost column are unchanged, you should clear/refill this yourself
+    ;      Carry flag determines if screen color data must be scrolled too
+
+    %asm {{
+        bcc _scroll_screen
+
++               ; scroll the screen and the color memory
+        ldx  #0
+        ldy  #38
+-
+        .for row=0, row<=24, row+=1
+            lda  f256.Screen + 40*row + 1,x
+            sta  f256.Screen + 40*row + 0,x
+            lda  f256.Colors + 40*row + 1,x
+            sta  f256.Colors + 40*row + 0,x
+        .next
+        inx
+        dey
+        bpl  -
+        rts
+
+_scroll_screen  ; scroll only the screen memory
+        ldx  #0
+        ldy  #38
+-
+        .for row=0, row<=24, row+=1
+            lda  f256.Screen + 40*row + 1,x
+            sta  f256.Screen + 40*row + 0,x
+        .next
+        inx
+        dey
+        bpl  -
+
+        rts
+    }}
+}
+
+asmsub  scroll_right  (bool alsocolors @ Pc) clobbers(A,X)  {
+    ; ---- scroll the whole screen 1 character to the right
+    ;      contents of the leftmost column are unchanged, you should clear/refill this yourself
+    ;      Carry flag determines if screen color data must be scrolled too
+    %asm {{
+        bcc  _scroll_screen
+
++               ; scroll the screen and the color memory
+        ldx  #38
+-
+        .for row=0, row<=24, row+=1
+            lda  f256.Screen + 40*row + 0,x
+            sta  f256.Screen + 40*row + 1,x
+            lda  f256.Colors + 40*row + 0,x
+            sta  f256.Colors + 40*row + 1,x
+        .next
+        dex
+        bpl  -
+        rts
+
+_scroll_screen  ; scroll only the screen memory
+        ldx  #38
+-
+        .for row=0, row<=24, row+=1
+            lda  f256.Screen + 40*row + 0,x
+            sta  f256.Screen + 40*row + 1,x
+        .next
+        dex
+        bpl  -
+
+        rts
+    }}
+}
+
+; stub for call moved to the f256 block.
+alias scroll_up = f256.scroll_up
+;asmsub  scroll_up  (bool alsocolors @ Pc) clobbers(A,X)  {
+;    %asm {{
+;        jmp f256.scroll_up
+;    }}
+;}
+
+asmsub  scroll_down  (bool alsocolors @ Pc) clobbers(A,X)  {
+    ; ---- scroll the whole screen 1 character down
+    ;      contents of the top row are unchanged, you should refill/clear this yourself
+    ;      Carry flag determines if screen color data must be scrolled too
+    %asm {{
+        bcc  _scroll_screen
+
++               ; scroll the screen and the color memory
+        ldx #39
+-
+        .for row=23, row>=0, row-=1
+            lda  f256.Colors + 40*row,x
+            sta  f256.Colors + 40*(row+1),x
+            lda  f256.Screen + 40*row,x
+            sta  f256.Screen + 40*(row+1),x
+        .next
+        dex
+        bpl  -
+        rts
+
+_scroll_screen  ; scroll only the screen memory
+        ldx #39
+-
+        .for row=23, row>=0, row-=1
+            lda  f256.Screen + 40*row,x
+            sta  f256.Screen + 40*(row+1),x
+        .next
+        dex
+        bpl  -
+
+        rts
+    }}
+}
+
+asmsub  setchr  (ubyte col @X, ubyte row @Y, ubyte character @A) clobbers(A, Y)  {
+    ; ---- sets the character in the screen matrix at the given position
+    %asm {{
+        pha                     ; preserve character
+        jsr  f256.chrptr             ; calculate offset
+        pla                     ; restore character
+        ldy  f256.io_ctrl       ; load current mapping
+        phy                     ; save on stack
+        ldy  #2
+        sty  f256.io_ctrl       ; map in screen memory
+        ldy  #0
+        sta  (f256.screen_ptr), y    ; write character
+        ply
+        sty  f256.io_ctrl       ; restore previous mapping
+        rts
+    }}
+}
+
+asmsub  getchr  (ubyte col @A, ubyte row @Y) clobbers(Y) -> ubyte @ A {
+    ; ---- get the character in the screen matrix at the given location
+    %asm  {{
+        phx                 ; preserve
+        tax                 ; move column to X for call
+        jsr  f256.chrptr         ; calculate offset to character
+        ldy  f256.io_ctrl   ; load current mapping
+        phy                 ; save on stack
+        ldy  #2
+        sty  f256.io_ctrl   ; map in screen memory
+        ldy  #0
+        lda  (f256.screen_ptr),y ; get character
+        ply
+        sty  f256.io_ctrl   ; restore previous mapping
+        plx                 ; restore
+        rts
+    }}
+}
+
+asmsub  setclr  (ubyte col @X, ubyte row @Y, ubyte color @A) clobbers(A, Y)  {
+    ; ---- set the color in A on the screen matrix at the given position
+    %asm {{
+        pha                     ; preserve character
+        jsr  f256.chrptr             ; calculate offset
+        pla                     ; restore character
+        ldy  f256.io_ctrl       ; load current mapping
+        phy                     ; save on stack
+        ldy  #3
+        sty  f256.io_ctrl       ; map in color memory
+        ldy  #0
+        sta  (f256.screen_ptr), y    ; write color
+        ply
+        sty  f256.io_ctrl       ; restore previous mapping
+        rts
+    }}
+}
+
+asmsub  getclr  (ubyte col @A, ubyte row @Y) clobbers(Y) -> ubyte @ A {
+    ; ---- get the color in the screen color matrix at the given location
+    %asm  {{
+        phx                 ; preserve
+        tax                 ; move column to X for call
+        jsr  f256.chrptr         ; calculate offset to character
+        ldy  f256.io_ctrl   ; load current mapping
+        phy                 ; save on stack
+        ldy  #3
+        sty  f256.io_ctrl   ; map in color memory
+        ldy  #0
+        lda  (f256.screen_ptr),y ; get color
+        ply
+        sty  f256.io_ctrl   ; restore previous mapping
+        plx                 ; restore
+        rts
+    }}
+}
+
+sub  setcc  (ubyte col, ubyte row, ubyte character, ubyte charcolor)  {
+    ; ---- set char+color at the given position on the screen
+    %asm {{
+        ldx  col                ; setup parameters
+        ldy  row
+        jsr  f256.chrptr             ; calculate offset
+        ldy  f256.io_ctrl       ; load current mapping
+        phy                     ; save on stack
+        ldy  #2
+        sty  f256.io_ctrl       ; map in screen memory
+        ldy  #0
+        lda  character
+        sta  (f256.screen_ptr), y
+        ldy  #3
+        sty  f256.io_ctrl       ; map in color memory
+        ldy  #0
+        lda  charcolor
+        sta  (f256.screen_ptr), y
+        ply                     ; previous mapping from stack
+        sty  f256.io_ctrl       ; restore previous map
+        rts
+    }}
+}
+
+asmsub  plot  (ubyte col @ Y, ubyte row @ X) {
+    %asm  {{
+        sty  f256.screen_col
+        stx  f256.screen_row
+        rts
+    }}
+}
+
+asmsub width() clobbers(X,Y) -> ubyte @A {
+    ; -- returns the text screen width (number of columns)
+    %asm {{
+        lda  DEFAULT_WIDTH
+        rts
+    }}
+}
+
+asmsub height() clobbers(X, Y) -> ubyte @A {
+    ; -- returns the text screen height (number of rows)
+    %asm {{
+        lda  DEFAULT_HEIGHT
+        rts
+    }}
+}
+
+; TODO: jmp to cbm.CHRIN?
+asmsub waitkey() -> ubyte @A {
+    %asm {{
+-       stz f256.event.type         ; invalidate existing event type
+        jsr f256.event.NextEvent
+        lda f256.event.type
+        cmp #f256.event.key.PRESSED
+        bne -
+        ;lda f256.event.key.raw ; return scan code?
+        lda f256.event.key.ascii    ; return upper or lower ASCII
+        rts
+    }}
+}
+}

examples/customtarget/readme.txt

@@ -1,5 +1,6 @@
 Various examples for configurable target machines, such as the NEO6502, Atari 800,
-and "tiny" example configurations for the X16 or C64 that provide more example materials.
+Foenix F256, and "tiny" example configurations for the X16 or C64 that provide
+more example materials.
 
 Look in the Makefile to see how to build or run the various programs.
 
@@ -7,4 +8,4 @@ The user 'adiee5' has been working on a Nintendo Entertainment System (NES) comp
 and example program, you can find those efforts here on GitHub: https://github.com/adiee5/prog8-nes-target
 Note that the NES is a very alien architecture for Prog8 still and the support is very limited
 (for example, prog8 is not aware that the program code usually is going to end up in a ROM cartridge,
-and currently still generates code that might nog work in ROM.)
+and currently still generates code that might not work in ROM.)

examples/customtarget/src/f256-hello.p8

@@ -0,0 +1,84 @@
+;
+; Simplistic example of some text output and
+; reading keys.
+;
+%launcher none
+%import textio
+
+main {
+    str hello = "Hello, World from Prog8!"
+
+    sub start() {
+        ubyte i
+        ubyte key
+
+        txt.cls()
+
+        txt.nl()
+        txt.print(hello)
+        txt.nl()
+
+        for i in 0 to 15 {
+            txt.color($f0 + i)
+            txt.print("This is color ")
+            txt.print_ub(i)
+            txt.nl()
+        }
+        txt.color($f2)
+
+        txt.row(30)
+        txt.print("Using setchr() to draw 'ABC'")
+        txt.nl()
+
+        txt.setchr(20, 20, 'A')
+        txt.setchr(21, 21, 'B')
+        txt.setchr(22, 22, 'C')
+
+        txt.nl()
+        txt.print("Using setchr(getchr()) to draw 'ABC'")
+        txt.nl()
+
+        txt.setchr(25, 25, txt.getchr(20, 20))
+        txt.setchr(26, 26, txt.getchr(21, 21))
+        txt.setchr(27, 27, txt.getchr(22, 22))
+
+        txt.setclr(20,20, $f3)
+        txt.setclr(21,21, $f4)
+        txt.setclr(22,22, $f5)
+
+        txt.setclr(25,25, txt.getclr(20,20))
+        txt.setclr(26,26, txt.getclr(21,21))
+        txt.setclr(27,27, txt.getclr(22,22))
+
+
+        txt.nl()
+        txt.print("Waiting for a key... ")
+        key = txt.waitkey()
+        txt.nl()
+        txt.print("KEY: ")
+        txt.chrout(key)
+        txt.nl()
+        txt.nl()
+
+        txt.print("Press keys to show them, ctrl-c resets machine.")
+        txt.nl()
+
+        ; look for keys forever
+        repeat {
+            void, key = cbm.GETIN()
+
+            if key != $00 {
+                txt.plot(0,40)
+                txt.print("key: ")
+                txt.chrout(key)
+                txt.spc()
+                txt.print_ubhex(key, true)
+            }
+
+            ; ctrl-c exists / resets machine
+            if key == $03
+                break
+        }
+    }
+}
+

examples/customtarget/targetconfigs/f256.properties

@@ -0,0 +1,55 @@
+# configuration file for a Foenix F256 Prog8 compilation target
+# generates '.bin' files that are in '.pgz' Foenix format.
+
+cpu = 65C02
+encoding = iso
+#output_type = LIBRARY
+output_type = RAW
+#load_address = $0200
+#load_address = $1000
+load_address = $2000
+memtop = $c000
+bss_highram_start = 0
+bss_highram_end = 0
+bss_goldenram_start = 0
+bss_goldenram_end = 0
+
+# io_regions specifies memory-mapped I/O registers that should be treated differentely.
+# it can be zero or more memory address ranges (inclusive) separated by comma
+io_regions = $c000-$dfff
+
+# zeropage scratch variables. zp_scratch_reg must always be zp_scratch_b1+1 !
+zp_scratch_b1 = $e2
+zp_scratch_reg = $e3
+zp_scratch_w1 = $e4
+zp_scratch_w2 = $e6
+
+# free zeropage locations for the various zp usage methods
+# zero or more zeropage address ranges (inclusive).
+#
+# $00-$01 - memory & I/O control (MMU)
+# $02-$07 - TODO: document (zp_scratch would fit here?)
+# $08-$0f - additional (optional) hardware registers (TODO: find & document)
+# ...
+# $e8-$ef - event array (8 bytes for next event)
+# $f0-$ff - kernel arguments table
+
+zp_fullsafe = $22-$e7
+zp_kernalsafe = $22-$e7
+zp_basicsafe = $22-$e7
+
+# the start of the 32 bytes used by the R0-R15 virtual registers. Can be in Zeropage or elsewhere.
+virtual_registers = $10
+
+# Where can we find the standard library (syslib.p8). You can still add more paths manually using -srcdirs
+library = ./libraries/f256
+
+# if a non-empty custom launcher code string is supplied, the compiler won't output ANY launcher / init code by itself,
+# and instead outputs whatever is specified here. (You can use \n here for newline and \ for line continuantions)
+custom_launcher_code =
+
+# additional options passed to the assembler program
+#assembler_options = --c256-pgx
+assembler_options = --c256-pgz --output-exec=$2000 
+#assembler_options = --output-exec=\$2000 --c256-pgz
+#--c256-pgz --output main.pgz