Listado de funciones externas

GO TO, CONTINUE, IF, STOP, FOR, NEXT, 
TO, STEP, GOSUB, RETURN, DEF, DIM,
AND, OR, NOT, XOR, REM, BREAK, NEW, CLEAR,

RANDOMIZE, RND, CODE, USR, BIN, ;, TAB, AT, LINE,
CLEAR, BEEP, PLAY, SAVE, LOAD, VERIFY, MERGE,

READ, DATA, RESTORE, VAL,

DIRMEM = Direccion de memoria de una variable, array, etc.
MEMCOPY, MEMSET = Transferencias de memoria
GETPIXEL, PUTPIXEL = Leer/Modificar pixel X,Y
DRAWTILE8X8, DRAWTILE16X16 = Dibujar UDG de 8x8 o 16x16 en posición Low-res (32x24).
GETTILE8X8, GETTILE16X16 = Leer UDG de 8x8 o 16x16 en posición Low-res (32x24).
DRAWTILEMAP8X8, DRAWTILEMAP16X16 = Dibujar un mapa de tiles 8x8 ó 16x16 en posición Low-Res (32x24)
INKEY$_RAW = Lectura raw de teclado (scancodes, sin traducir a ASCIIs).
PEEK16, POKE16 = Lectura/Escritura de 2 bytes consecutivos de memoria.
LISTS, STACKS, QUEUES, RINGS = Funciones de pilas, colas, listas y ringbuffers de enteros (IDs).
STRUCT = Estructuras de elementos enteros accesibles por (IX+N).
PIXELOFFSET, ATTRIBOFFSET, NEXTLINEOFFSET = Offset de un pixel X,Y en videoram o en zona de atributos.
HALT = Espera al retrazo de la pantalla (HALT en asm).

Nota: Este tema está relacionado con la convención de llamada a subrutina.

El formato para las llamadas externas será (…).

Ejemplo:

;----------------------------------------------------------------------
; FUNCTION: Function description
;
; INPUT:   (register list) as (what they represent)
; OUTPUT:  (register list) as (value)
; Uses:    (register list)
; Contributed by user - date
;----------------------------------------------------------------------

;----------------------------------------------------------------------
; CLS: Clears the screen with the char and attribute specified
;
; INPUT:  (DE) as (char,attrib) in stack
; OUTPUT: None
; Uses:   D, E, HL, A, A_shadow
;
; Contributed by sromero - 05-02-2008
;----------------------------------------------------------------------
CLS:
   pop hl       ; hl = return address
   ex (sp), hl  ; hl = x,y
   ex de, hl    ; de = x,y and (sp) = RETADDR
   ld a, e
   ex af, af    ; a_shadow = attribute
   ld a, d      ; a  = character
 
   ld hl, 16384
   ld (hl), a
   ld de, 16385
   ld bc, 6143
   ldir
 
   ex af, af
   ld hl, 16384+6144
   ld (hl), a
   ld de, 16384+6145
   ld bc, 768
   ldir
   ret

;----------------------------------------------------------------------
; ATTR: Returns ATTRIBUTE at (x,y) position
;           x,y is (0-N)
;
; INPUT:  (DE) as (x,y) in stack
; OUTPUT: A = ATTR (x,y)
; Uses:   DE, HL, A
;
; Contributed by sromero - 05-02-2008
;----------------------------------------------------------------------
ATTR:
  pop hl       ; hl = return address
  ex (sp), hl  ; hl = x,y
  ex de, hl    ; de = x,y and (sp) = RETADDR
 
  ; calc start address in DE (as (32*y) + x)
  ld h, 0
  ld l, d
  add hl, hl   ; HL = HL*2
  add hl, hl   ; HL = HL*4
  add hl, hl   ; HL = HL*8
  add hl, hl   ; HL = HL*16
  add hl, hl   ; HL = HL*32
  ld b, 88
  ld c, e
  add hl, bc
  ld a, (hl)
  ret

;----------------------------------------------------------------------
; SETATTR: Sets ATTRIBUTE at (x,y) position with value "v"
;           x,y is (0-N)
;
; INPUT:  (DE), (BC) as (x,y), (0,attribute) in stack
; OUTPUT: A = ATTR (x,y)
; Uses:   DE, BC, HL, A
; Contributed by sromero - 05-02-2008
;----------------------------------------------------------------------
SETATTR:
  pop hl       ; hl = return address
  pop bc       ; C = value (B value is ignored)
  ex (sp), hl  ; hl = x,y
  ex de, hl    ; de = x,y and (sp) = RETADDR
 
  ; calc start address in DE (as (32*y) + x)
  ld h, 0
  ld l, d
  add hl, hl   ; HL = HL*2
  add hl, hl   ; HL = HL*4
  add hl, hl   ; HL = HL*8
  add hl, hl   ; HL = HL*16
  add hl, hl   ; HL = HL*32
  ld d, 0
  add hl, de
  ld de, 22528
  add hl, de
  ld a, c
  ld (hl), a
  ret

;----------------------------------------------------------------------
; POKE: Writes an 8 bit value in a 16 bit memory address
;
; INPUT:  Address and Value directly assembled
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
POKE:
   LD (ADDRESS), VALUE

;----------------------------------------------------------------------
; PEEK: Reads an 8 bit value from a 16 bit memory address
;
; INPUT:  Address directly assembled
; OUTPUT: A as value (register)
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
PEEK:
   LD A, (ADDRESS)

;----------------------------------------------------------------------
; IN: Reads a value from an I/O port.
;
; INPUT:  Value Directly assembled
; OUTPUT: A as value (register)
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
IN:
   in a, (PORT)

;----------------------------------------------------------------------
; OUT: Sends a value to an I/O port.
;
; INPUT:  C, A as port,value (registers)
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
OUT:
   out (c), a

;----------------------------------------------------------------------
; BORDER: Clears the border with a given value
;
; INPUT:  A as value (register)
; OUTPUT: None
;
; Contributed by foro.speccy.org - 01-02-2008
;----------------------------------------------------------------------
BORDER:
   out (FEh), a

;----------------------------------------------------------------------
; SETBIT: Sets to 1 bit N in a given variable
;
; INPUT:  ADDRESS of var, and BITNUM directly assembled
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
SETBIT:
   ld hl, ADDRESS
   set BITNUM, (hl)

;----------------------------------------------------------------------
; RESETBIT: Sets to 0 bit N in a given variable
;
; INPUT:  ADDRESS of var, and BITNUM directly assembled
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
RESETBIT:
   ld hl, ADDRESS
   res BITNUM, (hl)

;----------------------------------------------------------------------
; TESTBIT: Checks if bit N in a given variable is 0 or 1
;
; INPUT:  ADDRESS of var, and BITNUM directly assembled
; OUTPUT: A = 0 or 1
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
TESTBIT:
   xor a               ; a = 0
   ld hl, ADDRESS
   bit BITNUM, (hl)
   jr z, 1             ; jr z, $+1 (jump the INC opcode)
   inc a               ; ZF = 0 -> bit not 0 -> a = 1
                       ; ZF = 1 -> bit = 0 -> a = 0

;----------------------------------------------------------------------
; SHIFT_LEFT (<<): Aritmetical Shift Left (INT VARIABLE = VARIABLE*2)
;
; INPUT:  DE as INTEGER register
; OUTPUT: DE rotated left
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
SHIFT_LEFT:
   SLA E
   RL D
 
   ; IX VERSION: Check which one is faster or better:
   ;
   ; LD IX, ADDRESS
   ; SLA (IX)
   ; RL (IX+01H)

;----------------------------------------------------------------------
; SHIFT_RIGHT (>>): Aritmetical Shift Right (INT VARIABLE = VARIABLE/2)
;
; INPUT:  DE as INTEGER register
; OUTPUT: DE rotated right
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
SHIFT_RIGHT:
   SRA D
   RR E
 
   ; IX VERSION: Check which one is faster or better:
   ;
   ; LD IX, ADDRESS
   ; SRA (IX+01H)
   ; RR (IX)

;----------------------------------------------------------------------
; A_AND (&): Logical AND in a 16 bit variable
;
; INPUT:  MEMORY_ADDRESS as destination, DE as 16 bit AND value
; OUTPUT: Modifies Memory address
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
A_AND:
   LD A, E
   AND (ADDRESS)
   LD A, D
   AND (ADDRESS+1)

;----------------------------------------------------------------------
; A_OR (|): Logical OR in a 16 bit variable
;
; INPUT:  MEMORY_ADDRESS as destination, DE as 16 bit OR value
; OUTPUT: Modifies Memory address
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
A_OR:
   LD A, E
   OR (ADDRESS)
   LD A, D
   OR (ADDRESS+1)

;----------------------------------------------------------------------
; A_XOR (^): Logical XOR in a 16 bit variable
;
; INPUT:  MEMORY_ADDRESS as destination, DE as 16 bit XOR value
; OUTPUT: Modifies Memory address
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
A_XOR:
   LD A, E
   XOR (ADDRESS)
   LD A, D
   XOR (ADDRESS+1)

Modificarán variables internas tipo “ZXB_CURRENT_ATTRIB” para ser usadas luego en PRINT, componiendo su valor con el de INK, PAPER, etc según qué dato se haya cambiado. Por ejemplo, una llamada a “INK 7”, metería el valor 7 en los 3 bits más bajos de la variable interna ZXB_CURRENT_ATTRIB.

;----------------------------------------------------------------------
; INK: Changes ZXB_CURRENT_ATTRIB bits 0-2 (INK)
;
; INPUT:  Value directly assembled
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
INK:
   LD A, 248                  ; Clear bits 0-2 
   AND (ZXB_CURRENT_ATTRIB)   ; of ZXB_CURRENT_ATTRIB
   LD A, VALUE
   AND 7                      ; Clear bits 7-3 of value
   OR (ZXB_CURRENT_ATTRIB)    ; Change ink in ZXB_CURRENT_ATTRIB

;----------------------------------------------------------------------
; PAPER: Changes ZXB_CURRENT_ATTRIB bits 3-6 (PAPER)
;
; INPUT:  Value directly assembled
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
PAPER:
   LD A, 199                  ; Clear bits 3-6
   AND (ZXB_CURRENT_ATTRIB)   ; of ZXB_CURRENT_ATTRIB
   LD A, VALUE
   AND 7                      ; Clear bits 7-3 of value
   SLA
   SLA
   SLA                        ; Shift Left A (3 times)
   OR (ZXB_CURRENT_ATTRIB)    ; Change paper in ZXB_CURRENT_ATTRIB

;----------------------------------------------------------------------
; BRIGHT: Changes ZXB_CURRENT_ATTRIB bit 6 (BRIGHT)
;
; INPUT:  Value directly assembled
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
BRIGHT:
   LD A, 191                  ; Clear bits 7 and 5-0
   AND (ZXB_CURRENT_ATTRIB)   ; of ZXB_CURRENT_ATTRIB
   LD A, VALUE
   RRC A
   RRC A                      ; Bit 0 -> Bit 6
   AND 191                    ; Clear bits 7 and 5-0
   OR (ZXB_CURRENT_ATTRIB)    ; Change bright in ZXB_CURRENT_ATTRIB

;----------------------------------------------------------------------
; FLASH: Changes ZXB_CURRENT_ATTRIB bit 7 (FLASH)
;
; INPUT:  Value directly assembled
; OUTPUT: None
;
; Contributed by sromero - 06-02-2008
;----------------------------------------------------------------------
FLASH:
   LD A, 127                  ; Clear bits 6-0
   AND (ZXB_CURRENT_ATTRIB)   ; of ZXB_CURRENT_ATTRIB
   LD A, VALUE
   RRC A                      ; Bit 0 -> Bit 7
   AND 127                    ; Clear bits 6-0
   OR (ZXB_CURRENT_ATTRIB)    ; Change flash in ZXB_CURRENT_ATTRIB

(etc.)