Common out boilerplate function prologue code; shrinks Star Trek from 44256 to

43892 bytes.

mach/i80/libem/pro.s

@@ -0,0 +1,58 @@
+.sect .text
+.sect .rom
+.sect .data
+.sect .bss
+.sect .text
+
+.define .proword, .probyte
+.define .pro0, .pro2, .pro4
+
+! BC is used as the frame pointer, but HL and DE can be corrupted.
+
+.proword:
+	pop h
+	push b
+	mov e, m
+	inx h
+	mov d, m
+	inx h
+	jmp .pron
+
+.probyte:
+	pop h
+	push b
+	mvi e, 0xff
+	mov d, m
+	inx h
+	jmp .pron
+
+.pro4:
+	pop h
+	push b
+	lxi d, -4
+	jmp .pron
+
+.pro2:
+	pop h
+	push b
+	lxi d, -2
+	jmp .pron
+
+.pro0:
+	pop h
+	push b
+	lxi d, 0
+	! fall through
+.pron:
+	shld .retadr
+	! Copy the current stack pointer to BC.
+	lxi h, 0
+	dad sp
+	mov b, h
+	mov c, l
+	! Calculate the new stack pointer.
+	dad d
+	sphl
+	lhld .retadr
+	pchl
+

mach/i80/ncg/mach.c

@@ -52,22 +52,18 @@ void con_mult(sz) word sz;
 #define FL_MSB_AT_LOW_ADDRESS 0
 #include <con_float>
 
-void prolog(nlocals) full nlocals;
+void prolog(full nlocals)
 {
-
+	if (nlocals == 0)
-	fprintf(codefile, "\tpush\tb\n\tlxi\th,0\n\tdad\tsp\n\tmov\tb,h\n\tmov\tc,l\n");
+		fprintf(codefile, "\tcall .pro0\n");
-	switch (nlocals)
+	else if (nlocals == 2)
-	{
+		fprintf(codefile, "\tcall .pro2\n");
-		case 4:
+	else if (nlocals == 4)
-			fprintf(codefile, "\tpush\th\n");
+		fprintf(codefile, "\tcall .pro4\n");
-		case 2:
+	else if (nlocals < 0x100)
-			fprintf(codefile, "\tpush\th\n");
+		fprintf(codefile, "\tcall .probyte\n\t.data1 %d\n", -nlocals);
-		case 0:
+	else
-			break;
+		fprintf(codefile, "\tcall .proword\n\t.data2 %d\n", -nlocals);
-		default:
-			fprintf(codefile, "\tlxi\th,%d\n\tdad\tsp\n\tsphl\n", -nlocals);
-			break;
-	}
 }
 
 void mes(type) word type;