edit

Makefile

@@ -48,7 +48,7 @@ trace.o charpoly.o hermite.o laguerre.o legendre.o degree.o divisors.o \
 vectorize.o variables.o test.o selftest.o numerator.o denominator.o simfac.o \
 besselj.o bessely.o carac.o convolution.o dirac.o erf.o erfc.o summarize.o \
 fourier.o gamma.o heaviside.o invfourier.o sgn.o cofactor.o adj.o \
-tchebychevT.o tchebychevU.o arg.o imag.o mag.o real.o rect.o
+tchebychevT.o tchebychevU.o arg.o imag.o mag.o real.o rect.o divpoly.o
 
 math : $(objects)
 	$(CXX) -o math $(objects) -lm

defs.h

@@ -93,6 +93,7 @@ enum {
 	DIRAC,
 	DISPLAY,
 	DIVISORS,
+	DIVPOLY,
 	DO,
 	DOT,
 	DRAW,

divpoly.cpp

@@ -1,4 +1,28 @@
+// Divide polynomials
+
 #include "stdafx.h"
+#include "defs.h"
+
+void
+eval_divpoly(void)
+{
+	push(cadr(p1));			// 1st arg, p(x)
+	eval();
+
+	push(caddr(p1));		// 2nd arg, q(x)
+	eval();
+
+	push(cadddr(p1));		// 3rd arg, x
+	eval();
+
+	p1 = pop();			// guess?
+	if (p1 == symbol(NIL))
+		guess();
+	else
+		push(p1);
+
+	divpoly();
+}
 
 //-----------------------------------------------------------------------------
 //
@@ -10,18 +34,15 @@
 //
 //			tos-1		x
 //
-//	Output:		tos-2		Quotient
-//
-//			tos-1		Remainder
+//	Output:		tos-1		Quotient
 //
 //-----------------------------------------------------------------------------
 
-#include "defs.h"
-
 #define DIVIDEND p1
 #define DIVISOR p2
 #define X p3
 #define Q p4
+#define QUOTIENT p5
 
 void
 divpoly(void)
@@ -51,7 +72,8 @@ divpoly(void)
 
 	x = m - n;
 
-	push(zero);
+	push_integer(0);
+	QUOTIENT = pop();
 
 	while (x >= 0) {
 
@@ -69,16 +91,34 @@ divpoly(void)
 			dividend[x + i] = pop();
 		}
 
+		push(QUOTIENT);
 		push(Q);
 		push(X);
 		push_integer(x);
 		power();
 		multiply();
 		add();
+		QUOTIENT = pop();
 
 		m--;
 		x--;
 	}
 
+	tos = h;
+
+	push(QUOTIENT);
+
 	restore();
 }
+
+static char *s[] = {
+
+	"divpoly(x^2+1,x)",
+	"x",
+};
+
+void
+test_divpoly(void)
+{
+	test(__FILE__, s, sizeof s / sizeof (char *));
+}

eval.cpp

@@ -103,6 +103,7 @@ eval_cons(void)
 	case DIRAC:		eval_dirac();		break;
 	case DISPLAY:		eval_display();		break;
 	case DIVISORS:		eval_divisors();	break;
+	case DIVPOLY:		eval_divpoly();		break;
 	case DO:		eval_do();		break;
 	case DOT:		eval_inner();		break;
 	case DRAW:		eval_draw();		break;

init.cpp

@@ -71,6 +71,7 @@ init(void)
 	std_symbol("dirac", DIRAC);
 	std_symbol("display", DISPLAY);
 	std_symbol("divisors", DIVISORS);
+	std_symbol("divpoly", DIVPOLY);
 	std_symbol("do", DO);
 	std_symbol("dot", DOT);
 	std_symbol("draw", DRAW);

prototypes.h

@@ -244,7 +244,9 @@ void divisors_onstack(void);
 void test_divisors(void);
 
 // divpoly.cpp
+void eval_divpoly(void);
 void divpoly(void);
+void test_divpoly(void);
 
 // draw.cpp
 void eval_draw(void);

selftest.cpp

@@ -59,6 +59,7 @@ selftest(void)
 	test_denominator();
 	test_derivative();
 	test_dirac();
+	test_divpoly();
 	test_erf();
 	test_erfc();
 	test_expcos();