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collapseos/cvm/vm.h
2020-06-28 19:45:28 -04:00

48 lines
1.4 KiB
C

#include <stdint.h>
#include <stdbool.h>
#define SP_ADDR 0xffff
#define RS_ADDR 0xff00
#define SYSVARS RS_ADDR-0x80
typedef uint8_t byte;
typedef uint16_t word;
// Native words in this C Forth VMs are indexed in an array. The word in memory
// is the typical 0x00 to indicate native, followed by an index byte. The
// Execute routine will then know which native word to execute.
typedef void (*NativeWord) ();
typedef byte (*IORD) ();
typedef void (*IOWR) (byte data);
/* Native word placement
Being a C VM, all actual native code is outside the VM's memory. However,
we have a stable ABI to conform to. VM_init() configures the memory by
placing references to stable words at proper offsets, and then add all other
native words next to it. This will result in a "boot binary" that is much
more compact than a real Collapse OS memory layout.
*/
typedef struct {
byte mem[0x10000];
word SP;
word RS;
word IP;
NativeWord nativew[0x100];
byte nativew_count;
// Array of 0x100 function pointers to IO read and write routines. Leave to
// NULL when IO port is unhandled.
IORD iord[0x100];
IOWR iowr[0x100];
word xcurrent; // only used during native bootstrap
word maxRS;
word minSP;
bool running;
bool uflw;
} VM;
VM* VM_init();
void VM_deinit();
bool VM_steps(int n);
void VM_memdump();
void VM_debugstr(char *s);
void VM_printdbg();