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Add MEMSIZE build-time parameter to set memory size

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By default, this is 128 (for 128KB).  Usable values are 128, 512,
1024, 2048, 4096.
This commit is contained in:
Matt Evans 2024-08-18 17:28:46 +01:00
parent 5449bb9697
commit f0ff05081c
3 changed files with 10 additions and 5 deletions
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2
Makefile
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@ -26,6 +26,7 @@
#
DEBUG ?= 0
MEMSIZE ?= 128
SOURCES = $(wildcard src/*.c)
@ -43,6 +44,7 @@ LIBS = $(SDL_LIBS) -lm
INCLUDEFLAGS = -Iinclude/ -I$(MUSASHI) $(SDL_CFLAGS) -DMUSASHI_CNF=\"../include/m68kconf.h\"
INCLUDEFLAGS += -DENABLE_DASM=1
INCLUDEFLAGS += -DUMAC_MEMSIZE=$(MEMSIZE)
CFLAGS = $(INCLUDEFLAGS) -Wall -Wextra -pedantic -DSIM
ifeq ($(DEBUG),1)

11
README.md
View file

@ -33,12 +33,14 @@ This emulates the following hardware:
* VIA shift register for keyboard
* SCC DCD pin change interrupts, for mouse
* Paravirtualised disc storage
* Defaults to 128K of RAM, but will run as a Mac 512K by changing
a `#define` (`RAM_SIZE`).
* Defaults to 128K of RAM, but will run as a Mac 512K by building
with `MEMSIZE=512`. Or, you could use 1024, 2048, or 4096 to
make a 1/2/4MB Mac Plus.
There's no emulation for:
* IWM/realistic floppy drives
* SCSI; the machine is sort of like a Mac Plus without SCSI.
* More than one disc, or runtime image-switching
* Sound (a lot of work for a beep)
* VIA timers (Space Invaders runs too fast, probably because of this)
@ -110,7 +112,8 @@ make
```
No surprises here. No autoconf either. :D You can add a `DEBUG=1` to
make to compile in debug spew.
make to compile in debug spew, and add `MEMSIZE=<size_in_KB>` to control
the amount of memory.
This will configure and build _Musashi_, umac, and `unix_main.c` as
the SDL2 frontend. The _Musashi_ build generates a few files
@ -185,7 +188,7 @@ pitfalls/observations:
(e.g. `Open()`, `Prime()`, `Control()`, `Status()`) the call is
routed to host-side C code in `disc.c`. The emulation code
doesn't support any of the advanced things a driver can be asked
to do, such as formatting – just read/[not yet write] of a block.
to do, such as formatting – just read/write of a block.
When the disc is asked to be ejected, a `umac` callback is called;
currently this just exits the emulator. The beginnings of
multi-disc support are there, but not enabled – again, bare

2
include/machw.h
View file

@ -31,7 +31,7 @@
#include "rom.h"
#define ROM_ADDR 0x400000 /* Regular base (and 0, when overlay=0 */
#define RAM_SIZE (0x20000*1)
#define RAM_SIZE (1024*UMAC_MEMSIZE)
#define RAM_HIGH_ADDR 0x600000
#define PV_SONY_ADDR 0xc00069 /* Magic address for replacement driver PV ops */