git.sur5r.net Git - cc65/blob - libsrc/lynx/cartread.s

   1 ; ***
   2 ; CC65 Lynx Library
   3 ;
   4 ; Originally by Bastian Schick
   5 ; http://www.geocities.com/SiliconValley/Byte/4242/lynx/
   6 ;
   7 ; Ported to cc65 (http://www.cc65.org) by
   8 ; Shawn Jefferson, June 2004
   9 ;
  10 ; ***
  11 ;
  12 ; void __fastcall__ read_cart_block(unsigned char block, char *dest)
  13 ;
  14 ; Reads an entire block (1024 bytes) from the cartridge into the buffer
  15 ; pointed to by dest.
  16
  17
  18         .export     _read_cart_block
  19         .import     FileSelectBlock, FileReadBytes
  20         .import     popa
  21
  22         .include    "extzp.inc"
  23
  24
  25 .code
  26
  27 ;*******************************************
  28 ; void read_cart_block (unsigned char block, char *dest);
  29 ; loads one Block (1024 bytes) to pDest
  30
  31 _read_cart_block:
  32         sta     _FileDestPtr            ;  lo
  33         stx     _FileDestPtr+1          ;  hi
  34
  35         jsr     popa                    ; bBlock
  36
  37         sta     _FileCurrBlock
  38         jsr     FileSelectBlock         ; select block# (Accu)
  39
  40         lda     #<1024                  ; load a whole block (1024 bytes)
  41         eor     #$ff
  42         tax
  43         lda     #>1024
  44         eor     #$ff
  45         tay
  46
  47         jmp     FileReadBytes
  48
  49