prim.c

#include <string.h>

#include "prim.h"
#include "desc.h"
#include "thunk.h"
#include "mem.h"

void __add(Thunk* target)
{
	Thunk* arg1 = stack[stack_top - 2];
	Thunk* arg2 = stack[stack_top - 1];
	
	arg1 = eval(arg1);
	arg2 = eval(arg2);
	
	updateI(target, readI(arg1) + readI(arg2));
}

void __sub(Thunk* target)
{
	Thunk* arg1 = stack[stack_top - 2];
	Thunk* arg2 = stack[stack_top - 1];
	
	arg1 = eval(arg1);
	arg2 = eval(arg2);
	
	updateI(target, readI(arg1) - readI(arg2));
}

void __gt(Thunk* target)
{
	Thunk* arg1 = stack[stack_top - 2];
	Thunk* arg2 = stack[stack_top - 1];
	
	arg1 = eval(arg1);
	arg2 = eval(arg2);
	
	updateB(target, readI(arg1) > readI(arg2));
}

void __lt(Thunk* target)
{
	Thunk* arg1 = stack[stack_top - 2];
	Thunk* arg2 = stack[stack_top - 1];
	
	arg1 = eval(arg1);
	arg2 = eval(arg2);
	
	updateB(target, readI(arg1) < readI(arg2));
}

void __eqI(Thunk* target)
{
	Thunk* arg1 = stack[stack_top - 2];
	Thunk* arg2 = stack[stack_top - 1];
	
	arg1 = eval(arg1);
	arg2 = eval(arg2);
	
	updateB(target, readI(arg1) == readI(arg2));
}

void __eqB(Thunk* target)
{
	Thunk* arg1 = stack[stack_top - 2];
	Thunk* arg2 = stack[stack_top - 1];
	
	arg1 = eval(arg1);
	arg2 = eval(arg2);
	
	updateB(target, readB(arg1) == readB(arg2));
}

void __not(Thunk* target)
{
	Thunk* arg1 = stack[stack_top - 1];
	
	arg1 = eval(arg1);
	
	updateB(target, !readB(arg1));
}

PrimEntry* add_prim(int arity, int strictness, char* name, void (*exec)(Thunk*))
{
	int nameLength = strlen(name);
	
	// before the PrimEntry there are "arity" number of SliceEntries
	SliceEntry* entry_base = (SliceEntry*) alloc_desc(sizeof(SliceEntry) * arity + sizeof(PrimEntry) + nameLength + 1);
		
	PrimEntry* entry = (PrimEntry*) (entry_base + arity);
	entry->base.type = FT_PRIM;
	entry->base.arity = arity;
	entry->strictness = strictness;
	entry->exec = exec;
	
	// TODO: should it be copied at all?
	memcpy(entry->name, name, nameLength);
	entry->name[nameLength] = '\0';
	
	// generate slices. avoid function call if arity is zero
	if(arity>0) gen_slices(entry_base, (Desc*) entry, arity);
	
	add_desc(entry->name, (Desc*) entry);
}

void init_prim()
{
	add_prim(2, 3, "add", &__add);
	add_prim(2, 3, "sub", &__sub);
	add_prim(2, 3, "gt", &__gt);
	add_prim(2, 3, "lt", &__lt);
	add_prim(2, 3, "eqI", &__eqI);
	add_prim(2, 3, "eqB", &__eqB);
	add_prim(1, 1, "not", &__not);
}