Difference between revisions of "Build tool/InstallRAMISR"
From MSX Game Library
| Line 13: | Line 13: | ||
<tt>_p0</tt> will be place in segment after your main program. Segment number depend of the mapper format your are using: | <tt>_p0</tt> will be place in segment after your main program. Segment number depend of the mapper format your are using: | ||
| − | + | {| class="wikitable" | |
| − | + | ! Mapper !! Segments | |
| − | + | |- | |
| − | + | | ASCII-8 || #4 and #5 | |
| + | |- | ||
| + | | ASCII-16 || #2 | ||
| + | |- | ||
| + | | KONAMI K4 || #4 and #5 | ||
| + | |- | ||
| + | | KONAMI K5 (SCC) || #4 and #5 | ||
| + | |- | ||
| + | | NEO-8 || #6 and #7 | ||
| + | |- | ||
| + | | NEO-16 || #3 | ||
| + | |} | ||
When you use this option, these segments are reserved for code and data to be copied on page 0 and cannot be used for anything else. | When you use this option, these segments are reserved for code and data to be copied on page 0 and cannot be used for anything else. | ||
Revision as of 01:22, 3 December 2024
Build tool option InstallRAMISR is used to automatically select RAM in page 0 then copy data there at startup, so ROM cartridge can take advantage of 16 KB of additional RAM.
As page 0 (addresses 0x0000-0x3FFF) is the place where MSX will search for interruption handler (ISR), the build tool will automatically copy the selected ISR (see CustomISR option).
InstallRAMISR can take 3 values:
- RAM0_NONE: Don't switch page 0 to RAM
- RAM0_ISR: Switch page 0 to RAM then install ISR at 0x0038 (mandatory address)
- RAM0_SEGMENT: Switch page 0 to RAM, install ISR at 0x0038 , then copy segment data (for mapped-ROM)
RAM0_SEGMENT
When using RAM0_SEGMENT option, you can define a source code file named {projectName}_p0.c (or .asm) and it will be automatically added to your mapper data and copy at statup in page 0. Code and data from your _p0 file will be available starting from address 0x0100 (after the ISR) so you have a little less than 16 KB available in page 0 (16 KB - 0x100 = 16128 bytes).
_p0 will be place in segment after your main program. Segment number depend of the mapper format your are using:
| Mapper | Segments |
|---|---|
| ASCII-8 | #4 and #5 |
| ASCII-16 | #2 |
| KONAMI K4 | #4 and #5 |
| KONAMI K5 (SCC) | #4 and #5 |
| NEO-8 | #6 and #7 |
| NEO-16 | #3 |
When you use this option, these segments are reserved for code and data to be copied on page 0 and cannot be used for anything else.