Difference between revisions of "Target"

From MSX Game Library

(→‎Setup)
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=== Data ===
 
=== Data ===
−
The first 32KB of the mapped-ROM is build like a 32KB plain ROM.
+
Mapped-ROM use a system of sub-page (called "bank" here) the user can point to any segment of the ROM.
−
This represents the first 4 segments for an 8KB mapper and the first 2 for a 16KB mapper.
+
Those bank are mapped to page 1 and 2 (4000h~BFFFh) of the memory space.
 +
The number of banks depends on the size of the mapper:
 +
* 8KB mappers have 4 banks:
 +
** bank 0: 4000h~5FFFh
 +
** bank 1: 6000h~7FFFh
 +
** bank 2: 8000h~9FFFh
 +
** bank 3: A000h~BFFFh
 +
* 16KB mappers have 2 banks:
 +
** bank 0: 4000h~7FFFh
 +
** bank 1: 8000h~BFFFh
  
−
The following segments are added to the ROM by the Build Tool by searching for files with a particular nomenclature: <project name>_s<segment number>_b<bank where the segment will be placed>
+
The Build Tool build the first 32KB of the mapped-ROM like a 32KB plain ROM.
 +
This represents the first 4 segments for a 8KB mapper and the first 2 for a 16KB mapper.
 +
 
 +
The following segments are added to the ROM by the Build Tool by searching for files with a particular nomenclature: <tt>''<project name>''_s''<segment_number>''_b''<target_bank>''.c</tt>.
 +
 
 +
 
 +
 
 +
program.c
 +
program_s4_b1.c
 +
program_s5_b1.c

Revision as of 13:47, 4 March 2022

Basic program

MSX-DOS program

Plain ROM program

Mapped ROM program

Setup

You can create program using one of this supported ROM mappers:

  • ASCII-8: 8KB segments for a total to 64KB to 2MB,
  • ASCII-16: 16KB segments for a total to 64KB to 4MB,
  • Konami: 8KB segments for a total to 64KB to 2MB,
  • Konami SCC: 8KB segments for a total to 64KB to 2MB.

In your build.bat, chose as target on of the following type: ROM_ASCII8, ROM_ASCII16, ROM_KONAMI, ROM_KONAMI_SCC. You can specify the ROM size (in KB) in the ROMSize variable. Default value is 128 (KB). Any multiple value of the mapper's segments size is valid, but I recommend using powers of 2 values (64, 128, 256, etc.) to help emulators to autodetect the right mapper.

Some Build Tool configuration examples: 

  REM -- 128KB ASCII-8 mapped-ROM
  set target=ROM_ASCII8

  REM -- 4MB ASCII-16 mapped-ROM
  set target=ROM_ASCII16
  set ROMSize=4096

  REM -- 512KB Konami SCC mapped-ROM
  set target=ROM_KONAMI_SCC
  set ROMSize=512

See s_vgm sample for a concrete use case.

Data

Mapped-ROM use a system of sub-page (called "bank" here) the user can point to any segment of the ROM. Those bank are mapped to page 1 and 2 (4000h~BFFFh) of the memory space. The number of banks depends on the size of the mapper:

  • 8KB mappers have 4 banks:
    • bank 0: 4000h~5FFFh
    • bank 1: 6000h~7FFFh
    • bank 2: 8000h~9FFFh
    • bank 3: A000h~BFFFh
  • 16KB mappers have 2 banks:
    • bank 0: 4000h~7FFFh
    • bank 1: 8000h~BFFFh

The Build Tool build the first 32KB of the mapped-ROM like a 32KB plain ROM. This represents the first 4 segments for a 8KB mapper and the first 2 for a 16KB mapper.

The following segments are added to the ROM by the Build Tool by searching for files with a particular nomenclature: <project name>_s<segment_number>_b<target_bank>.c.


program.c program_s4_b1.c program_s5_b1.c

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