Implement a tiny bit of CPM BDOS and add a corresponding Z80 core driver so that simple CPM programs like ZEXDOC/ZEXALL can be run against my Z80 core

1 files changed, 112 insertions, 0 deletions

diff --git a/blastcpm.c b/blastcpm.c
new file mode 100644
index 0000000..d964d70
--- /dev/null
+++ b/blastcpm.c
@@ -0,0 +1,112 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/select.h>
+
+#include "z80_to_x86.h"
+#include "util.h"
+
+uint8_t ram[64 * 1024];
+
+#define START_OFF 0x100
+#define OS_START 0xE400
+#define OS_RESET 0xE403
+int headless = 1;
+
+void z80_next_int_pulse(z80_context * context)
+{
+	context->int_pulse_start = context->int_pulse_end = CYCLE_NEVER;
+}
+
+void render_errorbox(char *title, char *message)
+{
+}
+
+void render_infobox(char *title, char *message)
+{
+}
+
+void *console_write(uint32_t address, void *context, uint8_t value)
+{
+	putchar(value);
+	return context;
+}
+
+uint8_t console_read(uint32_t address, void *context)
+{
+	return getchar();
+}
+
+void *console_flush_write(uint32_t address, void *context, uint8_t value)
+{
+	fflush(stdout);
+	return context;
+}
+
+uint8_t console_status_read(uint32_t address, void *context)
+{
+	fd_set read_fds;
+	FD_ZERO(&read_fds);
+	struct timeval timeout;
+	timeout.tv_sec = 0;
+	timeout.tv_usec = 0;
+	FD_SET(fileno(stdin), &read_fds);
+	return select(fileno(stdin)+1, &read_fds, NULL, NULL, &timeout) > 0; 
+}
+
+void *exit_write(uint32_t address, void *context, uint8_t value)
+{
+	exit(0);
+	return context;
+}
+
+const memmap_chunk z80_map[] = {
+	{ 0x0000, 0x10000,  0xFFFF, 0, MMAP_READ | MMAP_WRITE | MMAP_CODE, ram, NULL, NULL, NULL, NULL},
+};
+
+const memmap_chunk io_map[] = {
+	{ 0x0, 0x1, 0xFFFF, 0, 0, NULL, NULL, NULL, console_read, console_write},
+	{ 0x1, 0x2, 0xFFFF, 0, 0, NULL, NULL, NULL, console_status_read, console_flush_write},
+	{ 0x2, 0x3, 0xFFFF, 0, 0, NULL, NULL, NULL, NULL, exit_write},
+};
+
+int main(int argc, char **argv)
+{
+	FILE *f = fopen("fake_cpm.bin", "rb");
+	long fsize = file_size(f);
+	if (fsize > sizeof(ram) - OS_START) {
+		fsize = sizeof(ram) - OS_START;
+	}
+	if (fread(ram + OS_START, 1, fsize, f) != fsize) {
+		fprintf(stderr, "Error reading from fake_cpm.bin\n");
+		exit(1);
+	}
+	f = fopen(argv[1], "rb");
+	fsize = file_size(f);
+	if (fsize > OS_START - START_OFF) {
+		fsize = OS_START - START_OFF;
+	}
+	if (fread(ram + START_OFF, 1, fsize, f) != fsize) {
+		fprintf(stderr, "Error reading from file %s\n", argv[1]);
+		exit(1);
+	}
+	fclose(f);
+	ram[0] = 0xC3;
+	ram[1] = OS_RESET & 0xFF;
+	ram[2] = OS_RESET >> 8;
+	ram[5] = 0xC3;
+	ram[6] = OS_START & 0xFF;
+	ram[7] = OS_START >> 8;
+	
+	z80_options opts;
+	z80_context context;
+	init_z80_opts(&opts, z80_map, 1, io_map, 3, 1);
+	init_z80_context(&context, &opts);
+	for(;;)
+	{
+		z80_run(&context, 1000000);
+		context.current_cycle = 0;
+	}
+	return 0;
+}
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