retrodeluxe/sdcc-msx

Fork of sdcc that provides msx specific extensions

sdcc-msx

Fork of sdcc that provides msx specific extensions (mz80)

• Added page command line options

  -bo  <num>             use code page <num>
  -ba  <num>             use data page <num>
  

• Added pragmas CODE_PAGE and DATA_PAGE to select code and data pages inside a module

• Added support for "--model-large"

  • This will make functions banked unless otherwise specified with __nonbanked

  • Every banked call is replaced with

    call __sdcc_banked_call
    dw function_addr (LSB, MSB)
    ds bank (HIB)
    

  • Base bank 24bit addresses need to be provided to the linker

    -b _CODE_PAGE_1=0x1A000 -b _CODE_PAGE_2=0x2A000 ... -B _DATA_PAGE_3=0x38000 ... etc
    

  • The linker will resolve banked calls based on the segment each symbol belongs to based on bo, ba and pragma bank

  Note that as bank number comes from the high byte of the 24bit address of the page, is only possible to use one type of page (either CODE or DATA) per 0x10000 address range, even if they are not overlapping.

  • __sdcc_banked_call must be implemented in an non-banked area (HOME or CODE) and is up to the user An example for ASCII8 ROMs can be found here: https://github.com/retrodeluxe/rlengine-msx1/blob/linker_exp/boot/bootASCII8.s

Known issues

• Banked function pointers are (obviously) not supported, but they can be handled manually.

Todo

• Add an msx specific sub port instead of using mz80
• Add support for R800 MUL* instructions

Conversion from Intel Hex Format to MSX ROM

• The Linker produces an IHX file with 24bit address space that needs to be split into pages of the appropiate size and assembled as a ROM file. This can be done by modifying the hex2bin tool accordingly.
• An example for ASCII8 ROMs can be found here: https://github.com/retrodeluxe/rlengine-msx1/blob/linker_exp/tools/hex2rom.c