3b1emu: src/state.c@15ae2788e848 (annotated)

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src/state.c@15ae2788e848 (annotated)

src/state.c

Tue, 15 Jan 2013 17:02:56 +0000

author: Philip Pemberton <philpem@philpem.me.uk>
date: Tue, 15 Jan 2013 17:02:56 +0000
changeset 121: 15ae2788e848
parent 112: a392eb8f9806
child 138: d744db15cdf7
permissions: -rw-r--r--

Implement m68k_read_disassembler_* properly

The previous implementations of m68k_read_disassembler are unsuitable due to
interactions with the memory mapper. A read from memory by the DASM should not
mutate system state.

So we modify the m68k_read_disassembler_{8,16,32} functions to do the memory
mapping themselves without causing page faults (bus error exception) or
updating the page flag bits (which could really upset the kernel).

Now all we need is a debugger/disassembler...

 #define _STATE_C
 #include <stddef.h>
 #include <malloc.h>
 #include <stdio.h>
 #include "wd279x.h"
 #include "wd2010.h"
 #include "keyboard.h"
 #include "state.h"
 int state_init(size_t base_ram_size, size_t exp_ram_size)
 {
 	// Free RAM if it's allocated
 	if (state.base_ram != NULL)
 		free(state.base_ram);
 	if (state.exp_ram != NULL)
 		free(state.exp_ram);
 	// Initialise hardware registers
 	state.romlmap = false;
 	state.idmarw = state.dmaen = state.dmaenb = false;
 	state.dma_count = state.dma_address = 0;
 	state.pie = 0;
 	state.ee = 0;
 	state.leds = 0;
 	state.genstat = 0;				// FIXME: check this
 	state.bsr0 = state.bsr1 = 0;	// FIXME: check this
 	state.timer_enabled = state.timer_asserted = false;
 	// Allocate Base RAM, making sure the user has specified a valid RAM amount first
 	// Basically: 512KiB minimum, 2MiB maximum, in increments of 512KiB.
 	if ((base_ram_size < 512*1024) || (base_ram_size > 2048*1024) || ((base_ram_size % (512*1024)) != 0))
 		return -1;
 	state.base_ram = malloc(base_ram_size);
 	if (state.base_ram == NULL)
 		return -2;
 	state.base_ram_size = base_ram_size;
 	// Now allocate expansion RAM
 	// The difference here is that we can have zero bytes of Expansion RAM; we're not limited to having a minimum of 512KiB.
 	if ((exp_ram_size > 2048*1024) || ((exp_ram_size % (512*1024)) != 0))
 		return -1;
 	state.exp_ram = malloc(exp_ram_size);
 	if (state.exp_ram == NULL)
 		return -2;
 	state.exp_ram_size = exp_ram_size;
 	// Load ROMs
 	FILE *r14c, *r15c;
 	r14c = fopen("roms/14c.bin", "rb");
 	if (r14c == NULL) {
 		fprintf(stderr, "[state] Error loading roms/14c.bin.\n");
 		return -3;
 	}
 	r15c = fopen("roms/15c.bin", "rb");
 	if (r15c == NULL) {
 		fprintf(stderr, "[state] Error loading roms/15c.bin.\n");
 		return -3;
 	}
 	// get ROM file size
 	fseek(r14c, 0, SEEK_END);
 	size_t romlen = ftell(r14c);
 	fseek(r14c, 0, SEEK_SET);
 	fseek(r15c, 0, SEEK_END);
 	size_t romlen2 = ftell(r15c);
 	fseek(r15c, 0, SEEK_SET);
 	if (romlen2 != romlen) {
 		fprintf(stderr, "[state] ROMs are not the same size!\n");
 		return -3;
 	}
 	if ((romlen + romlen2) > ROM_SIZE) {
 		fprintf(stderr, "[state] ROM files are too large!\n");
 		return -3;
 	}
 	// sanity checks completed; load the ROMs!
 	uint8_t *romdat1, *romdat2;
 	romdat1 = malloc(romlen);
 	romdat2 = malloc(romlen2);
 	fread(romdat1, 1, romlen, r15c);
 	fread(romdat2, 1, romlen2, r14c);
 	// convert the ROM data
 	for (size_t i=0; i<(romlen + romlen2); i+=2) {
 		state.rom[i+0] = romdat1[i/2];
 		state.rom[i+1] = romdat2[i/2];
 	}
 	// TODO: if ROM buffer not filled, repeat the ROM data we read until it is (wraparound emulation)
 	// free the data arrays and close the files
 	free(romdat1);
 	free(romdat2);
 	fclose(r14c);
 	fclose(r15c);
 	// Initialise the disc controller
 	wd2797_init(&state.fdc_ctx);
 	// Initialise the keyboard controller
 	keyboard_init(&state.kbd);
 	return 0;
 }
 void state_done()
 {
 	if (state.base_ram != NULL) {
 		free(state.base_ram);
 		state.base_ram = NULL;
 	}
 	if (state.exp_ram != NULL) {
 		free(state.exp_ram);
 		state.exp_ram = NULL;
 	}
 	// Deinitialise the disc controller
 	wd2797_done(&state.fdc_ctx);
 	wd2010_done(&state.hdc_ctx);
 }

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src/state.c@15ae2788e848 (annotated)

src/state.c