factor/vm/callbacks.cpp

106 lines
2.5 KiB
C++

#include "master.hpp"
namespace factor
{
callback_heap::callback_heap(cell size, factor_vm *parent_) :
seg(new segment(size,true)),
here(seg->start),
parent(parent_) {}
callback_heap::~callback_heap()
{
delete seg;
seg = NULL;
}
void factor_vm::init_callbacks(cell size)
{
callbacks = new callback_heap(size,this);
}
void callback_heap::store_callback_operand(code_block *stub, cell index, cell value)
{
tagged<array> code_template(parent->special_objects[CALLBACK_STUB]);
cell rel_class = untag_fixnum(array_nth(code_template.untagged(),3 * index + 1));
cell rel_type = untag_fixnum(array_nth(code_template.untagged(),3 * index + 2));
cell offset = untag_fixnum(array_nth(code_template.untagged(),3 * index + 3));
relocation_entry rel(
(relocation_type)rel_type,
(relocation_class)rel_class,
offset);
instruction_operand op(rel,stub,0);
op.store_value(value);
}
void callback_heap::update(code_block *stub)
{
store_callback_operand(stub,1,(cell)callback_xt(stub));
stub->flush_icache();
}
code_block *callback_heap::add(cell owner, cell return_rewind)
{
tagged<array> code_template(parent->special_objects[CALLBACK_STUB]);
tagged<byte_array> insns(array_nth(code_template.untagged(),0));
cell size = array_capacity(insns.untagged());
cell bump = align(size + sizeof(code_block),data_alignment);
if(here + bump > seg->end) fatal_error("Out of callback space",0);
free_heap_block *free_block = (free_heap_block *)here;
free_block->make_free(bump);
here += bump;
code_block *stub = (code_block *)free_block;
stub->owner = owner;
stub->parameters = false_object;
stub->relocation = false_object;
memcpy(stub->xt(),insns->data<void>(),size);
/* Store VM pointer */
store_callback_operand(stub,0,(cell)parent);
/* On x86, the RET instruction takes an argument which depends on
the callback's calling convention */
#if defined(FACTOR_X86) || defined(FACTOR_AMD64)
store_callback_operand(stub,2,return_rewind);
#endif
update(stub);
return stub;
}
struct callback_updater {
callback_heap *callbacks;
explicit callback_updater(callback_heap *callbacks_) : callbacks(callbacks_) {}
void operator()(code_block *stub)
{
callbacks->update(stub);
}
};
void callback_heap::update()
{
callback_updater updater(this);
each_callback(updater);
}
void factor_vm::primitive_callback()
{
cell return_rewind = to_cell(ctx->pop());
tagged<word> w(ctx->pop());
w.untag_check(this);
ctx->push(allot_alien(callbacks->add(w.value(),return_rewind)->xt()));
}
}