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Added an instruction setup

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op_t provides opcodes, inst_t provides a wrapper with operands.  vm_t
carries around a pointer to a set of instructions, and vm_execute
attempts to execute that one.  I do some weird stuff here, and it's
definitely not complete.
This commit is contained in:
Aryadev Chavali
2023-10-15 05:52:58 +01:00
parent 3786b7d785
commit ea14b3beb6
1 changed files with 61 additions and 0 deletions
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61
src/main.c
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@@ -15,6 +15,28 @@
#include "./base.h" #include "./base.h"
typedef enum
{
OP_PUSH_BYTE = 1,
OP_PUSH_WORD,
OP_PUSH_FLOAT,
} op_t;
typedef struct
{
op_t opcode;
data_t operand;
} inst_t;
#define INST_BPUSH(BYTE) \
((inst_t){.opcode = OP_PUSH_BYTE, .operand = DBYTE(BYTE)})
#define INST_WPUSH(WORD) \
((inst_t){.opcode = OP_PUSH_WORD, .operand = DWORD(WORD)})
#define INST_FPUSH(FLOAT) \
((inst_t){.opcode = OP_PUSH_FLOAT, .operand = DFLOAT(FLOAT)})
typedef struct typedef struct
{ {
struct Stack struct Stack
@@ -22,8 +44,20 @@ typedef struct
byte *data; byte *data;
word ptr, max; word ptr, max;
} stack; } stack;
struct Program
{
inst_t *instructions;
word ptr, max;
} program;
} vm_t; } vm_t;
void vm_load_program(vm_t *vm, inst_t *instructions, size_t size)
{
vm->program.instructions = instructions;
vm->program.max = size;
vm->program.ptr = 0;
}
void vm_load_stack(vm_t *vm, byte *bytes, size_t size) void vm_load_stack(vm_t *vm, byte *bytes, size_t size)
{ {
vm->stack.data = bytes; vm->stack.data = bytes;
@@ -101,6 +135,33 @@ f64 vm_pop_float(vm_t *vm)
return f; return f;
} }
typedef void (*push_f)(vm_t *, data_t);
void vm_execute(vm_t *vm)
{
struct Program *prog = &vm->program;
if (prog->ptr >= prog->max)
// TODO: Error (Went past end of program)
return;
inst_t instruction = prog->instructions[prog->ptr];
// NOTE: This is ballsy; I'm essentially saying I will never use the
// last 2 bits unless it's a push routine
if ((instruction.opcode & 0b11) != 0)
{
// Push routine
const push_f routines[] = {[OP_PUSH_BYTE] = vm_push_byte,
[OP_PUSH_WORD] = vm_push_word,
[OP_PUSH_FLOAT] = vm_push_float};
routines[instruction.opcode](vm, instruction.operand);
prog->ptr++;
}
else
{
// TODO: Error (Unknown opcode)
return;
}
}
#define ARR_SIZE(xs) (sizeof(xs) / sizeof(xs[0])) #define ARR_SIZE(xs) (sizeof(xs) / sizeof(xs[0]))
int main(void) int main(void)