Add pushc and popc directives

src/asm/asmy.y

@@ -621,6 +621,8 @@ static void strsubUTF8(char *dest, const char *src, uint32_t pos, uint32_t len)
 %token	T_POP_CHARMAP
 %token	T_POP_NEWCHARMAP
 %token	T_POP_SETCHARMAP
+%token	T_POP_PUSHC
+%token	T_POP_POPC
 %token	T_POP_SHIFT
 %token	T_POP_ENDR
 %token	T_POP_FAIL
@@ -776,6 +778,8 @@ simple_pseudoop : include
 		| charmap
 		| newcharmap
 		| setcharmap
+		| pushc
+		| popc
 		| rept
 		| shift
 		| fail
@@ -1047,11 +1051,19 @@ newcharmap	: T_POP_NEWCHARMAP T_ID
 		{
 			charmap_New($2, $4);
 		}
+;
 
 setcharmap	: T_POP_SETCHARMAP T_ID
 		{
 			charmap_Set($2);
 		}
+;
+
+pushc		: T_POP_PUSHC	{ charmap_Push(); }
+;
+
+popc		: T_POP_POPC	{ charmap_Pop(); }
+;
 
 printt		: T_POP_PRINTT string
 		{

src/asm/charmap.c

@@ -20,11 +20,18 @@
 
 #define CHARMAP_HASH_SIZE (1 << 9)
 
+struct CharmapStackEntry {
+	struct Charmap *charmap;
+	struct CharmapStackEntry *next;
+};
+
 static struct Charmap *tHashedCharmaps[CHARMAP_HASH_SIZE];
 
 static struct Charmap *mainCharmap;
 static struct Charmap *currentCharmap;
 
+struct CharmapStackEntry *charmapStack;
+
 static void warnSectionCharmap(void)
 {
 	static bool warned = false;
@@ -119,6 +126,32 @@ void charmap_Set(const char *name)
 	currentCharmap = *ppCharmap;
 }
 
+void charmap_Push(void)
+{
+	struct CharmapStackEntry *stackEntry;
+
+	stackEntry = malloc(sizeof(struct CharmapStackEntry));
+	if (stackEntry == NULL)
+		fatalerror("No memory for charmap stack");
+
+	stackEntry->charmap = currentCharmap;
+	stackEntry->next = charmapStack;
+
+	charmapStack = stackEntry;
+}
+
+void charmap_Pop(void)
+{
+	if (charmapStack == NULL)
+		fatalerror("No entries in the charmap stack");
+
+	struct CharmapStackEntry *top = charmapStack;
+
+	currentCharmap = top->charmap;
+	charmapStack = top->next;
+	free(top);
+}
+
 void charmap_InitMain(void)
 {
 	mainCharmap = charmap_New("main", NULL);

src/asm/globlex.c

@@ -481,6 +481,8 @@ const struct sLexInitString lexer_strings[] = {
 	{"charmap", T_POP_CHARMAP},
 	{"newcharmap", T_POP_NEWCHARMAP},
 	{"setcharmap", T_POP_SETCHARMAP},
+	{"pushc", T_POP_PUSHC},
+	{"popc", T_POP_POPC},
 
 	{"fail", T_POP_FAIL},
 	{"warn", T_POP_WARN},

src/asm/rgbasm.5

@@ -1146,7 +1146,8 @@ a different encoding for other purposes, for example. Initially, there is
 one character map called
 .Sy main
 and it is automatically selected as the current character map from the
-beginning.
+beginning. There is also a character map stack that can be used to save and
+restore which character map is currently active.
 .Bl -column "NEWCHARMAP name, basename"
 .It Sy Command Ta Sy Meaning
 .It Ic NEWCHARMAP Ar name Ta Creates a new, empty character map called
@@ -1156,6 +1157,8 @@ beginning.
 copied from character map
 .Ic basename .
 .It Ic SETCHARMAP Ar name Ta Switch to character map Ic name .
+.It Ic PUSHC Ta Push the current character map onto the stack.
+.It Ic POPC Ta Pop a character map off the stack and switch to it.
 .El
 .Pp
 .Sy Note: