Added reporting of division by zero errors rather than crashing

etc/mkuxn-fast.lua

@@ -72,9 +72,15 @@ pop_push = function(k, n, s)
     return nil
   end
 end
+local indented_block
+indented_block = function(s)
+  s = s:gsub('^%{ *', '{\n'):gsub('\n', '\n\t'):gsub('\t%} *$', '}\n')
+  s = s:gsub('\n[^\n]+%.error = [^\n]+', '%0\n#ifndef NO_STACK_CHECKS\n\tgoto error;\n#endif')
+  return s
+end
 local process
 process = function(body)
-  local out_body = body:gsub('^%{ *', ''):gsub(' *%}$', ''):gsub('; ', ';\n'):gsub('(%a+)(%d+)(%b())', pop_push)
+  local out_body = body:gsub('^%{ *', ''):gsub(' *%}$', ''):gsub('; ', ';\n'):gsub('%b{} *', indented_block):gsub('(%a+)(%d+)(%b())', pop_push)
   local in_ifdef = false
   local _list_0 = {
     'src',
@@ -132,6 +138,8 @@ for l in assert(io.lines('src/uxn.c')) do
     if replacements[name] then
       body = replacements[name]
     end
+    body = body:gsub('u%-%>src%-%>', 'src.')
+    body = body:gsub('u%-%>dst%-%>', 'dst.')
     body = body:gsub('u%-%>src', 'src')
     body = body:gsub('u%-%>dst', 'dst')
     top = {
@@ -278,6 +286,7 @@ See etc/mkuxn-fast.moon for instructions.
 
 */
 ]])
+  wanted = true
   while true do
     local _continue_0 = false
     repeat
@@ -287,9 +296,19 @@ See etc/mkuxn-fast.moon for instructions.
         break
       end
       if l == '/* Stack */' then
+        wanted = false
+      end
+      if l:match('errors%[%]') then
+        _with_0:write('\n#ifndef NO_STACK_CHECKS\n')
+        wanted = true
+      end
+      if wanted then
+        _with_0:write(('%s\n'):format(l))
+      end
+      if l == '}' then
+        _with_0:write('#endif\n\n')
         break
       end
-      _with_0:write(('%s\n'):format(l))
       _continue_0 = true
     until true
     if not _continue_0 then
@@ -338,12 +357,10 @@ evaluxn(Uxn *u, Uint16 vec)
 	return 1;
 #ifndef NO_STACK_CHECKS
 error:
-	printf("Halted: %s-stack %sflow#%04x, at 0x%04x\n",
+	if(u->wst.error)
-		u->wst.error ? "Working" : "Return",
+		return haltuxn(u, u->wst.error, "Working-stack", instr);
-		((u->wst.error | u->rst.error) & 2) ? "over" : "under",
+	else
-		instr,
+		return haltuxn(u, u->rst.error, "Return-stack", instr);
-		u->ram.ptr);
-	return 0;
 #endif
 }
 

etc/mkuxn-fast.moon

@@ -77,8 +77,13 @@ pop_push = (k, n, s) ->
 		else
 			nil
 
+indented_block = (s) ->
+	s = s\gsub('^%{ *', '{\n')\gsub('\n', '\n\t')\gsub('\t%} *$', '}\n')
+	s = s\gsub('\n[^\n]+%.error = [^\n]+', '%0\n#ifndef NO_STACK_CHECKS\n\tgoto error;\n#endif')
+	s
+
 process = (body) ->
-	out_body = body\gsub('^%{ *', '')\gsub(' *%}$', '')\gsub('; ', ';\n')\gsub '(%a+)(%d+)(%b())', pop_push
+	out_body = body\gsub('^%{ *', '')\gsub(' *%}$', '')\gsub('; ', ';\n')\gsub('%b{} *', indented_block)\gsub '(%a+)(%d+)(%b())', pop_push
 	in_ifdef = false
 	for k in *{'src', 'dst'}
 		if bottom[k] != 0
@@ -115,6 +120,8 @@ for l in assert io.lines 'src/uxn.c'
 		continue
 	if replacements[name]
 		body = replacements[name]
+	body = body\gsub 'u%-%>src%-%>', 'src.'
+	body = body\gsub 'u%-%>dst%-%>', 'dst.'
 	body = body\gsub 'u%-%>src', 'src'
 	body = body\gsub 'u%-%>dst', 'dst'
 	top = { src: 0, dst: 0 }
@@ -200,13 +207,21 @@ See etc/mkuxn-fast.moon for instructions.
 
 */
 ]]
+	wanted = true
 	while true
 		l = f\read '*l'
 		if l\match' push' or l\match'[ *]pop'
 			continue
 		if l == '/* Stack */'
+			wanted = false
+		if l\match 'errors%[%]'
+			\write '\n#ifndef NO_STACK_CHECKS\n'
+			wanted = true
+		if wanted
+			\write '%s\n'\format l
+		if l == '}'
+			\write '#endif\n\n'
 			break
-		\write '%s\n'\format l
 	\write [[
 /* clang-format on */
 
@@ -238,12 +253,10 @@ evaluxn(Uxn *u, Uint16 vec)
 	return 1;
 #ifndef NO_STACK_CHECKS
 error:
-	printf("Halted: %s-stack %sflow#%04x, at 0x%04x\n",
+	if(u->wst.error)
-		u->wst.error ? "Working" : "Return",
+		return haltuxn(u, u->wst.error, "Working-stack", instr);
-		((u->wst.error | u->rst.error) & 2) ? "over" : "under",
+	else
-		instr,
+		return haltuxn(u, u->rst.error, "Return-stack", instr);
-		u->ram.ptr);
-	return 0;
 #endif
 }
 

src/uxn-fast.c

@@ -34,6 +34,19 @@ void   mempoke16(Uint8 *m, Uint16 a, Uint16 b) { mempoke8(m, a, b >> 8); mempoke
 Uint16 mempeek16(Uint8 *m, Uint16 a) { return (mempeek8(m, a) << 8) + mempeek8(m, a + 1); }
 void   devpoke16(Device *d, Uint8 a, Uint16 b) { devpoke8(d, a, b >> 8); devpoke8(d, a + 1, b); }
 Uint16 devpeek16(Device *d, Uint16 a) { return (devpeek8(d, a) << 8) + devpeek8(d, a + 1); }
+
+#ifndef NO_STACK_CHECKS
+static const char *errors[] = {"underflow", "overflow", "division by zero"};
+
+int
+haltuxn(Uxn *u, Uint8 error, char *name, int id)
+{
+	printf("Halted: %s %s#%04x, at 0x%04x\n", name, errors[error - 1], id, u->ram.ptr);
+	u->ram.ptr = 0;
+	return 0;
+}
+#endif
+
 /* clang-format on */
 
 #pragma mark - Core
@@ -453,6 +466,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_1b_DIV:");
 			{
 				Uint8 a = u->wst.dat[u->wst.ptr - 1], b = u->wst.dat[u->wst.ptr - 2];
+				if(a == 0) {
+					u->wst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->wst.dat[u->wst.ptr - 2] = b / a;
 #ifndef NO_STACK_CHECKS
 				if(__builtin_expect(u->wst.ptr < 2, 0)) {
@@ -926,6 +946,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_3b_DIV2:");
 			{
 				Uint16 a = (u->wst.dat[u->wst.ptr - 1] | (u->wst.dat[u->wst.ptr - 2] << 8)), b = (u->wst.dat[u->wst.ptr - 3] | (u->wst.dat[u->wst.ptr - 4] << 8));
+				if(a == 0) {
+					u->wst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->wst.dat[u->wst.ptr - 4] = (b / a) >> 8;
 				u->wst.dat[u->wst.ptr - 3] = (b / a) & 0xff;
 #ifndef NO_STACK_CHECKS
@@ -1376,6 +1403,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_5b_DIVr:");
 			{
 				Uint8 a = u->rst.dat[u->rst.ptr - 1], b = u->rst.dat[u->rst.ptr - 2];
+				if(a == 0) {
+					u->rst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->rst.dat[u->rst.ptr - 2] = b / a;
 #ifndef NO_STACK_CHECKS
 				if(__builtin_expect(u->rst.ptr < 2, 0)) {
@@ -1849,6 +1883,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_7b_DIV2r:");
 			{
 				Uint16 a = (u->rst.dat[u->rst.ptr - 1] | (u->rst.dat[u->rst.ptr - 2] << 8)), b = (u->rst.dat[u->rst.ptr - 3] | (u->rst.dat[u->rst.ptr - 4] << 8));
+				if(a == 0) {
+					u->rst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->rst.dat[u->rst.ptr - 4] = (b / a) >> 8;
 				u->rst.dat[u->rst.ptr - 3] = (b / a) & 0xff;
 #ifndef NO_STACK_CHECKS
@@ -2332,6 +2373,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_9b_DIVk:");
 			{
 				Uint8 a = u->wst.dat[u->wst.ptr - 1], b = u->wst.dat[u->wst.ptr - 2];
+				if(a == 0) {
+					u->wst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->wst.dat[u->wst.ptr] = b / a;
 #ifndef NO_STACK_CHECKS
 				if(__builtin_expect(u->wst.ptr < 2, 0)) {
@@ -2846,6 +2894,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_bb_DIV2k:");
 			{
 				Uint16 a = (u->wst.dat[u->wst.ptr - 1] | (u->wst.dat[u->wst.ptr - 2] << 8)), b = (u->wst.dat[u->wst.ptr - 3] | (u->wst.dat[u->wst.ptr - 4] << 8));
+				if(a == 0) {
+					u->wst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->wst.dat[u->wst.ptr] = (b / a) >> 8;
 				u->wst.dat[u->wst.ptr + 1] = (b / a) & 0xff;
 #ifndef NO_STACK_CHECKS
@@ -3349,6 +3404,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_db_DIVkr:");
 			{
 				Uint8 a = u->rst.dat[u->rst.ptr - 1], b = u->rst.dat[u->rst.ptr - 2];
+				if(a == 0) {
+					u->rst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->rst.dat[u->rst.ptr] = b / a;
 #ifndef NO_STACK_CHECKS
 				if(__builtin_expect(u->rst.ptr < 2, 0)) {
@@ -3863,6 +3925,13 @@ evaluxn(Uxn *u, Uint16 vec)
 			__asm__("evaluxn_fb_DIV2kr:");
 			{
 				Uint16 a = (u->rst.dat[u->rst.ptr - 1] | (u->rst.dat[u->rst.ptr - 2] << 8)), b = (u->rst.dat[u->rst.ptr - 3] | (u->rst.dat[u->rst.ptr - 4] << 8));
+				if(a == 0) {
+					u->rst.error = 3;
+#ifndef NO_STACK_CHECKS
+					goto error;
+#endif
+					a = 1;
+				}
 				u->rst.dat[u->rst.ptr] = (b / a) >> 8;
 				u->rst.dat[u->rst.ptr + 1] = (b / a) & 0xff;
 #ifndef NO_STACK_CHECKS
@@ -3961,12 +4030,10 @@ evaluxn(Uxn *u, Uint16 vec)
 	return 1;
 #ifndef NO_STACK_CHECKS
 error:
-	printf("Halted: %s-stack %sflow#%04x, at 0x%04x\n",
+	if(u->wst.error)
-		u->wst.error ? "Working" : "Return",
+		return haltuxn(u, u->wst.error, "Working-stack", instr);
-		((u->wst.error | u->rst.error) & 2) ? "over" : "under",
+	else
-		instr,
+		return haltuxn(u, u->rst.error, "Return-stack", instr);
-		u->ram.ptr);
-	return 0;
 #endif
 }
 

src/uxn.c

@@ -61,7 +61,7 @@ void op_deo(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); devpoke8(&u->dev
 void op_add(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b + a); }
 void op_sub(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b - a); }
 void op_mul(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b * a); }
-void op_div(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b / a); }
+void op_div(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); if(a == 0) { u->src->error = 3; a = 1; } push8(u->src, b / a); }
 void op_and(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b & a); }
 void op_ora(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b | a); }
 void op_eor(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b ^ a); }
@@ -95,7 +95,7 @@ void op_deo16(Uxn *u) { Uint8 a = pop8(u->src); Uint16 b = pop16(u->src); devpok
 void op_add16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b + a); }
 void op_sub16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b - a); }
 void op_mul16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b * a); }
-void op_div16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b / a); }
+void op_div16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); if(a == 0) { u->src->error = 3; a = 1; } push16(u->src, b / a); }
 void op_and16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b & a); }
 void op_ora16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b | a); }
 void op_eor16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->src, b ^ a); }
@@ -117,10 +117,12 @@ void (*ops[])(Uxn *u) = {
 
 #pragma mark - Core
 
+static const char *errors[] = {"underflow", "overflow", "division by zero"};
+
 int
-haltuxn(Uxn *u, char *name, int id)
+haltuxn(Uxn *u, Uint8 error, char *name, int id)
 {
-	printf("Halted: %s#%04x, at 0x%04x\n", name, id, u->ram.ptr);
+	printf("Halted: %s %s#%04x, at 0x%04x\n", name, errors[error - 1], id, u->ram.ptr);
 	u->ram.ptr = 0;
 	return 0;
 }
@@ -145,9 +147,9 @@ stepuxn(Uxn *u, Uint8 instr)
 {
 	opcuxn(u, instr);
 	if(u->wst.error)
-		return haltuxn(u, u->wst.error == 1 ? "Working-stack underflow" : "Working-stack overflow", instr);
+		return haltuxn(u, u->wst.error, "Working-stack", instr);
 	if(u->rst.error)
-		return haltuxn(u, u->rst.error == 1 ? "Return-stack underflow" : "Return-stack overflow", instr);
+		return haltuxn(u, u->rst.error, "Return-stack", instr);
 	return 1;
 }