altos/lisp: Change lisp objects to use ao_poly everywhere. Add const

This makes all lisp objects use 16-bit ints for references so we can
hold more stuff in small amounts of memory. Also adds a separate
constant pool of lisp objects for builtins, initial atoms and constant
lisp code.

Now builds (and runs!) on the nucleo-32 boards.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 187 insertions, 2 deletions

diff --git a/src/lisp/ao_lisp_builtin.c b/src/lisp/ao_lisp_builtin.c
index 3752a2c8..e6d55797 100644
--- a/src/lisp/ao_lisp_builtin.c
+++ b/src/lisp/ao_lisp_builtin.c
@@ -15,7 +15,192 @@
 #include "ao_lisp.h"
 
 void
-ao_lisp_builtin_print(struct ao_lisp_builtin *b)
+ao_lisp_builtin_print(ao_poly b)
 {
-	printf("[builtin %s]", b->name);
+	(void) b;
+	printf("[builtin]");
 }
+
+enum math_op { math_plus, math_minus, math_times, math_divide, math_mod };
+
+ao_poly
+ao_lisp_car(struct ao_lisp_cons *cons)
+{
+	if (!cons) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	if (!cons->car) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	if (ao_lisp_poly_type(cons->car) != AO_LISP_CONS) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	return ao_lisp_poly_cons(cons->car)->car;
+}
+
+ao_poly
+ao_lisp_cdr(struct ao_lisp_cons *cons)
+{
+	if (!cons) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	if (!cons->car) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	if (ao_lisp_poly_type(cons->car) != AO_LISP_CONS) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	return ao_lisp_poly_cons(cons->car)->cdr;
+}
+
+ao_poly
+ao_lisp_cons(struct ao_lisp_cons *cons)
+{
+	ao_poly	car, cdr;
+	if (!cons) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	car = cons->car;
+	cdr = cons->cdr;
+	if (!car || !cdr) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	cdr = ao_lisp_poly_cons(cdr)->car;
+	if (ao_lisp_poly_type(cdr) != AO_LISP_CONS) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	return ao_lisp_cons_poly(ao_lisp_cons_cons(car, ao_lisp_poly_cons(cdr)));
+}
+
+ao_poly
+ao_lisp_quote(struct ao_lisp_cons *cons)
+{
+	if (!cons) {
+		ao_lisp_exception |= AO_LISP_INVALID;
+		return AO_LISP_NIL;
+	}
+	return cons->car;
+}
+
+ao_poly
+ao_lisp_print(struct ao_lisp_cons *cons)
+{
+	ao_poly	val = AO_LISP_NIL;
+	while (cons) {
+		val = cons->car;
+		ao_lisp_poly_print(val);
+		cons = ao_lisp_poly_cons(cons->cdr);
+	}
+	return val;
+}
+
+ao_poly
+ao_lisp_math(struct ao_lisp_cons *cons, enum math_op op)
+{
+	ao_poly	ret = AO_LISP_NIL;
+
+	while (cons) {
+		ao_poly		car = cons->car;
+		uint8_t		rt = ao_lisp_poly_type(ret);
+		uint8_t		ct = ao_lisp_poly_type(car);
+
+		cons = ao_lisp_poly_cons(cons->cdr);
+
+		if (rt == AO_LISP_NIL)
+			ret = car;
+
+		else if (rt == AO_LISP_INT && ct == AO_LISP_INT) {
+			int	r = ao_lisp_poly_int(ret);
+			int	c = ao_lisp_poly_int(car);
+
+			switch(op) {
+			case math_plus:
+				r += c;
+				break;
+			case math_minus:
+				r -= c;
+				break;
+			case math_times:
+				r *= c;
+				break;
+			case math_divide:
+				if (c == 0) {
+					ao_lisp_exception |= AO_LISP_DIVIDE_BY_ZERO;
+					return AO_LISP_NIL;
+				}
+				r /= c;
+				break;
+			case math_mod:
+				if (c == 0) {
+					ao_lisp_exception |= AO_LISP_DIVIDE_BY_ZERO;
+					return AO_LISP_NIL;
+				}
+				r %= c;
+				break;
+			}
+			ret = ao_lisp_int_poly(r);
+		}
+
+		else if (rt == AO_LISP_STRING && ct == AO_LISP_STRING && op == math_plus)
+			ret = ao_lisp_string_poly(ao_lisp_string_cat(ao_lisp_poly_string(ret),
+								     ao_lisp_poly_string(car)));
+		else {
+			ao_lisp_exception |= AO_LISP_INVALID;
+			return AO_LISP_NIL;
+		}
+	}
+	return ret;
+}
+
+ao_poly
+ao_lisp_plus(struct ao_lisp_cons *cons)
+{
+	return ao_lisp_math(cons, math_plus);
+}
+
+ao_poly
+ao_lisp_minus(struct ao_lisp_cons *cons)
+{
+	return ao_lisp_math(cons, math_minus);
+}
+
+ao_poly
+ao_lisp_times(struct ao_lisp_cons *cons)
+{
+	return ao_lisp_math(cons, math_times);
+}
+
+ao_poly
+ao_lisp_divide(struct ao_lisp_cons *cons)
+{
+	return ao_lisp_math(cons, math_divide);
+}
+
+ao_poly
+ao_lisp_mod(struct ao_lisp_cons *cons)
+{
+	return ao_lisp_math(cons, math_mod);
+}
+
+ao_lisp_func_t ao_lisp_builtins[] = {
+	[builtin_car] = ao_lisp_car,
+	[builtin_cdr] = ao_lisp_cdr,
+	[builtin_cons] = ao_lisp_cons,
+	[builtin_quote] = ao_lisp_quote,
+	[builtin_print] = ao_lisp_print,
+	[builtin_plus] = ao_lisp_plus,
+	[builtin_minus] = ao_lisp_minus,
+	[builtin_times] = ao_lisp_times,
+	[builtin_divide] = ao_lisp_divide,
+	[builtin_mod] = ao_lisp_mod
+};
+