BIOS

At initial boot time, the ROM bank containing the BIOS is banked in. The BIOS initializes the hardware, such as the UART and the video chip, and tries to load the steckOS loader executable (usually LOADER.PRG) from SD card and executes it. If that fails, the BIOS expects a PRG binary uploaded via XMODEM. UART baud rate and the name of the steckOS loader executable can be configured and are stored in the RTC’s NVRAM.

jumptable

filesystem | kernel | sdcard | spi | textui | video |

filesystem

krn_chdir | krn_close | krn_fopen | krn_fread_byte | krn_fseek | krn_getcwd | krn_mkdir | krn_open | krn_opendir | krn_read_direntry | krn_readdir | krn_rmdir | krn_unlink | krn_update_direntry | krn_write_byte |

krn_chdir

change current directory

In

A, low byte of pointer to zero terminated string with the file path
X, high byte of pointer to zero terminated string with the file path

Out

C, C=0 on success (A=0), C=1 and A= otherwise
X, index into fd_area of the opened directory (which is FD_INDEX_CURRENT_DIR)

krn_close

close file, update dir entry and free file descriptor quietly

library

fat32 | joystick | keyboard | sdcard | spi | uart | util | vdp |

fat32

fat_chdir | fat_close | fat_fopen | fat_fread_byte | fat_fread_vollgas | fat_fseek | fat_get_root_and_pwd | fat_mkdir | fat_mount | fat_opendir | fat_read_direntry | fat_readdir | fat_rmdir | fat_unlink | fat_update_direntry | fat_write_byte |

fat_chdir

change current directory

In

A, low byte of pointer to zero terminated string with the file path
X, high byte of pointer to zero terminated string with the file path

Out

C, C=0 on success (A=0), C=1 and A= otherwise
X, index into fd_area of the opened directory (which is FD_INDEX_CURRENT_DIR)

fat_close

close file, update dir entry and free file descriptor quietly