shithub: scc

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Add spill()

This function spill variable associated to a register into memory.

--- a/cc2/cc2.h

+++ b/cc2/cc2.h

@@ -53,8 +53,10 @@

 struct symbol {

 	unsigned short id;

 	char *name;

+	char kind;

 	bool public : 1;

 	bool extrn : 1;

+	bool dirty : 1;

 	union {

 		/* TODO: Admit inmediate of other type */

 		TINT imm;

--- a/cc2/cgen.c

+++ b/cc2/cgen.c

@@ -12,10 +12,10 @@

 static uint8_t lower[] = {[DE] = E, [HL] = L, [BC] = C, [IY] = IYL};

 static uint8_t pair[] = {

 	[A] = A,

-	[H] = HL, [L] = HL,

-	[B] = BC, [C] = BC,

-	[D] = DE, [E] = DE,

-	[IYL] = IY, [IYH] = IY

+	[H] = HL, [L] = HL, [HL] = HL,

+	[B] = BC, [C] = BC, [BC] = BC,

+	[D] = DE, [E] = DE, [DE] = DE,

+	[IYL] = IY, [IYH] = IY, [IY] = IY

 };

 Node

@@ -117,6 +117,41 @@

 }

 static void

+spill(uint8_t reg)

+{

+	Node *np, *r;

+	Symbol *sym;

+	uint8_t p, h, l;

+

+	if ((np = reguse[reg]) == NULL)

+		return;

+	if ((sym = np->sym) == NULL)

+		goto freereg;

+	if (!sym->dirty)

+		goto freereg;

+

+	r = regs[reg];

+	switch (np->type.size) {

+	case 1:

+		code(LDL, np, r);

+		break;

+	default:

+		abort();

+	}

+	sym->dirty = 0;

+

+freereg:

+	reguse[reg] = NULL;

+	p = pair[reg];

+	l = lower[p];

+	h = upper[p];

+	if (reg >= NREGS)

+		reguse[l] = reguse[h] = NULL;

+	else if (!reguse[l] && !reguse[h])

+		reguse[p] = NULL;

+}

+

+static void

 moveto(Node *np, uint8_t reg)

 {

 	Node *r = regs[reg], *u = reguse[reg];

@@ -127,7 +162,7 @@

 		if (op == u->op && sym && sym == u->sym)

 			return;

 		else

-			; /* TODO: Push the value? */

+			spill(reg);

 	}

 	switch (np->type.size) {

@@ -164,7 +199,7 @@

 	default:

 		abort();

 	}

-	reguse[reg] = np;

+	reguse[pair[reg]] = reguse[reg] = np;

 	np->op = REG;

 	np->reg = reg;

 }

@@ -176,31 +211,17 @@

 }

 static void

-push(uint8_t reg)

-{

-	Node *np;

-

-	if (reg < NREGS)

-		reg = pair[reg];

-	if ((np = reguse[lower[reg]]) != NULL)

-		np->op = PUSHED;

-	if ((np = reguse[upper[reg]]) != NULL)

-		np->op = PUSHED;

-	code(PUSH, NULL, regs[reg]);

-}

-

-static void

 accum(Node *np)

 {

+	Symbol *sym;

+

 	switch (np->type.size) {

 	case 1:

-		if (reguse[A])

-			push(A);

+		spill(A);

 		moveto(np, A);

 		break;

 	case 2:

-		if (reguse[H] || reguse[L])

-			push(HL);

+		spill(HL);

 		moveto(np, HL);

 		break;

 	case 4:

@@ -214,14 +235,13 @@

 {

 	Node *u = reguse[HL];

-	if (u) {

-		Symbol *sym = np->sym;

-

-		if (u->op == INDEX && sym && sym == u->sym) {

+	if (u && u->sym) {

+		if (u->op == INDEX && np->sym == u->sym) {

 			np->op = INDEX;

 			return;

-		} else

-			; /* TODO: Push the value? */

+		} else {

+			spill(HL);

+		}

 	}

 	code(LDI, &reg_HL, np);

 	np->op = INDEX;

@@ -295,7 +315,7 @@

 				break;

 			default:

 				abort();

-			}		

+			}

 			break;			

 		default:

 			abort();

@@ -316,6 +336,7 @@

 assign(Node *np)

 {

 	Node *lp = np->left, *rp = np->right;

+	Symbol *sym = lp->sym;

 	assert(rp->op == REG);

 	switch (np->type.size) {

@@ -340,6 +361,9 @@

 	default:

 		abort();

 	}

+

+	if (sym)

+		sym->dirty = 0;

 	np->op = REG;

 	np->reg = rp->reg;

 }

--- a/cc2/parser.c

+++ b/cc2/parser.c

@@ -287,12 +287,15 @@

 static Symbol *

 symbol(uint8_t t, char *token)

 {

+	Symbol *sym;

 	static Symbol *(*tbl[3])(char *)= {

 		[LOCAL] = local,

 		[GLOBAL] = global,

 		[PARAMETER] = parameter

 	};

-	return (*tbl[t])(token+1);

+	sym = (*tbl[t])(token+1);

+	sym->kind = *token;

+	return sym;

 }

 static void