Class: YABFI::VM
- Inherits:
-
Object
- Object
- YABFI::VM
- Defined in:
- ext/yabfi/vm.c,
ext/yabfi/vm.c,
ext/yabfi/vm.c
Overview
This class, which is implemented as a C extension, executes the instructions generated by the upstream ruby pipeline.
Defined Under Namespace
Classes: InvalidCommand, MemoryOutOfBounds
Instance Method Summary collapse
-
#execute! ⇒ nil
Execute the instructions loaded into the VM.
-
#initialize(input, output, eof) ⇒ Object
constructor
Initialize a new VM.
-
#load!(ary) ⇒ nil
Load the VM with new instructions.
-
#state ⇒ Object
Return the VM’s internal state – used in testing and debugging.
Constructor Details
#initialize(input, output, eof) ⇒ Object
Initialize a new VM.
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# File 'ext/yabfi/vm.c', line 143
static VALUE
vm_initialize(VALUE self, VALUE input, VALUE output, VALUE rb_eof) {
vm *ptr;
Check_Type(rb_eof, T_FIXNUM);
Data_Get_Struct(self, vm, ptr);
ptr->input = input;
ptr->output = output;
ptr->eof = NUM2INT(rb_eof);
return self;
};
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Instance Method Details
#execute! ⇒ nil
Execute the instructions loaded into the VM.
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# File 'ext/yabfi/vm.c', line 221
static VALUE
vm_execute(VALUE self) {
vm *ptr;
int *tmp_memory;
int delta;
int iter;
instruction curr;
Data_Get_Struct(self, vm, ptr);
while (ptr->program_counter < ptr->instructions_size) {
curr = ptr->instructions[ptr->program_counter];
switch (curr.code) {
case INSTRUCTION_CHANGE_VALUE:
ptr->memory[ptr->memory_cursor] += curr.argument;
ptr->program_counter++;
break;
case INSTRUCTION_CHANGE_POINTER:
if (((int) ptr->memory_cursor + curr.argument) < 0) {
rb_raise(rb_cMemoryOutOfBounds, "The memory cursor went below zero");
}
ptr->memory_cursor += curr.argument;
while (ptr->memory_cursor >= ptr->memory_size) {
delta = ptr->memory_size;
if (delta > MAX_REALLOCATION) {
delta = MAX_REALLOCATION;
}
tmp_memory = ptr->memory;
ptr->memory = malloc((ptr->memory_size + delta) * sizeof(int));
memcpy(ptr->memory, tmp_memory, ptr->memory_size * sizeof(int));
memset(ptr->memory + ptr->memory_size, 0, delta * sizeof(int));
ptr->memory_size += delta;
free(tmp_memory);
}
ptr->program_counter++;
break;
case INSTRUCTION_BRANCH_IF_ZERO:
if (ptr->memory[ptr->memory_cursor] == 0) {
ptr->program_counter += curr.argument;
} else {
ptr->program_counter++;
}
break;
case INSTRUCTION_BRANCH_NOT_ZERO:
if (ptr->memory[ptr->memory_cursor] != 0) {
ptr->program_counter += curr.argument;
} else {
ptr->program_counter++;
}
break;
case INSTRUCTION_GET:
for (iter = 0; iter < curr.argument; iter++) {
if (rb_funcall(ptr->input, rb_intern("eof?"), 0)) {
ptr->memory[ptr->memory_cursor] = ptr->eof;
} else {
ptr->memory[ptr->memory_cursor] =
FIX2INT(rb_funcall(ptr->input, rb_intern("getbyte"), 0));
}
}
ptr->program_counter++;
break;
case INSTRUCTION_PUT:
if (ptr->buffer_size < curr.argument) {
free(ptr->buffer);
ptr->buffer_size = curr.argument;
ptr->buffer = malloc(ptr->buffer_size * sizeof(char));
}
memset(ptr->buffer, ptr->memory[ptr->memory_cursor],
curr.argument * sizeof(char));
rb_funcall(ptr->output, rb_intern("write"), 1,
rb_str_new(ptr->buffer, curr.argument));
ptr->program_counter++;
break;
default:
rb_raise(rb_cInvalidCommand, "Invalid command code: %i", curr.code);
}
}
return Qnil;
}
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#load!(ary) ⇒ nil
Load the VM with new instructions.
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# File 'ext/yabfi/vm.c', line 169
static VALUE
vm_load(VALUE self, VALUE ary) {
int iter;
vm *ptr;
VALUE entry, code, arg;
Data_Get_Struct(self, vm, ptr);
Check_Type(ary, T_ARRAY);
vm_free(ptr);
ptr->memory_cursor = 0;
ptr->memory_size = INITIAL_MEMORY_SIZE;
ptr->memory = calloc(INITIAL_MEMORY_SIZE, sizeof(int));
ptr->program_counter = 0;
ptr->instructions_size = RARRAY_LEN(ary);
ptr->instructions = malloc(sizeof(instruction) * ptr->instructions_size);
ptr->buffer_size = INITIAL_BUFFER_SIZE;
ptr->buffer = malloc(INITIAL_BUFFER_SIZE * sizeof(char));
for (iter = 0; iter < (int) ptr->instructions_size; iter++) {
entry = rb_ary_entry(ary, iter);
Check_Type(entry, T_ARRAY);
if (RARRAY_LEN(entry) != 2) {
rb_raise(rb_cInvalidCommand, "Commands must be tuples");
}
code = rb_ary_entry(entry, 0);
arg = rb_ary_entry(entry, 1);
Check_Type(code, T_FIXNUM);
Check_Type(arg, T_FIXNUM);
ptr->instructions[iter] = (instruction) { FIX2INT(code), FIX2INT(arg) };
}
return Qnil;
}
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#state ⇒ Object
Return the VM’s internal state – used in testing and debugging.
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# File 'ext/yabfi/vm.c', line 305
static VALUE
vm_state(VALUE self) {
vm *ptr;
VALUE hash;
Data_Get_Struct(self, vm, ptr);
hash = rb_hash_new();
rb_hash_aset(hash, ID2SYM(rb_intern("memory_cursor")),
INT2FIX(ptr->memory_cursor));
rb_hash_aset(hash, ID2SYM(rb_intern("memory_size")),
INT2FIX(ptr->memory_size));
rb_hash_aset(hash, ID2SYM(rb_intern("program_counter")),
INT2FIX(ptr->program_counter));
if (ptr->memory_cursor < ptr->memory_size) {
rb_hash_aset(hash, ID2SYM(rb_intern("current_value")),
INT2FIX(ptr->memory[ptr->memory_cursor]));
} else {
rb_hash_aset(hash, ID2SYM(rb_intern("current_value")), Qnil);
}
return hash;
}
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