Fix linking tiny overlay files (#755)

* Fix compatibility of rgblink -O and -t

The -t "tiny mode" option makes ROM0 cover 0x8000 bytes,
not 0x4000. The -O "overlay" option fills areas uncovered
by sections with data from an overlay file. These needed
to cooperate so that the calculated uncovered overlay size
does not exceed the actual size of the ROM.

Fixes #754

* Print link test names like asm tests do

* Make the three test.sh scripts more similar

src/link/output.c

@@ -17,7 +17,11 @@
 
 #include "extern/err.h"
 
-FILE * outputFile;
+#include "linkdefs.h"
+
+#define BANK_SIZE 0x4000
+
+FILE *outputFile;
 FILE *overlayFile;
 FILE *symFile;
 FILE *mapFile;
@@ -103,43 +107,63 @@ struct Section const *out_OverlappingSection(struct Section const *section)
 
 /**
  * Performs sanity checks on the overlay file.
+ * @return The number of ROM banks in the overlay file
  */
-static void checkOverlay(void)
+static uint32_t checkOverlaySize(void)
 {
 	if (!overlayFile)
-		return;
+		return 0;
 
 	if (fseek(overlayFile, 0, SEEK_END) != 0) {
 		warnx("Overlay file is not seekable, cannot check if properly formed");
-		return;
+		return 0;
 	}
 
 	long overlaySize = ftell(overlayFile);
 
-	if (overlaySize % 0x4000)
-		errx(1, "Overlay file must have a size multiple of 0x4000");
-
 	/* Reset back to beginning */
 	fseek(overlayFile, 0, SEEK_SET);
 
-	uint32_t nbOverlayBanks = overlaySize / 0x4000 - 1;
+	if (overlaySize % BANK_SIZE)
+		errx(1, "Overlay file must have a size multiple of 0x4000");
 
-	if (nbOverlayBanks < 1)
+	uint32_t nbOverlayBanks = overlaySize / BANK_SIZE;
+
+	if (is32kMode && nbOverlayBanks != 2)
+		errx(1, "Overlay must be exactly 0x8000 bytes large");
+
+	if (nbOverlayBanks < 2)
 		errx(1, "Overlay must be at least 0x8000 bytes large");
 
-	if (nbOverlayBanks > sections[SECTTYPE_ROMX].nbBanks) {
+	return nbOverlayBanks;
+}
+
+/**
+ * Expand sections[SECTTYPE_ROMX].banks to cover all the overlay banks.
+ * This ensures that writeROM will output each bank, even if some are not
+ * covered by any sections.
+ * @param nbOverlayBanks The number of banks in the overlay file
+ */
+static void coverOverlayBanks(uint32_t nbOverlayBanks)
+{
+	/* 2 if is32kMode, 1 otherwise */
+	uint32_t nbRom0Banks = maxsize[SECTTYPE_ROM0] / BANK_SIZE;
+	/* Discount ROM0 banks to avoid outputting too much */
+	uint32_t nbUncoveredBanks = nbOverlayBanks - nbRom0Banks > sections[SECTTYPE_ROMX].nbBanks
+				    ? nbOverlayBanks - nbRom0Banks
+				    : 0;
+
+	if (nbUncoveredBanks > sections[SECTTYPE_ROMX].nbBanks) {
 		sections[SECTTYPE_ROMX].banks =
 			realloc(sections[SECTTYPE_ROMX].banks,
-				sizeof(*sections[SECTTYPE_ROMX].banks) *
-					nbOverlayBanks);
+				sizeof(*sections[SECTTYPE_ROMX].banks) * nbUncoveredBanks);
 		if (!sections[SECTTYPE_ROMX].banks)
 			err(1, "Failed to realloc banks for overlay");
-		for (uint32_t i = sections[SECTTYPE_ROMX].nbBanks;
-		     i < nbOverlayBanks; i++) {
+		for (uint32_t i = sections[SECTTYPE_ROMX].nbBanks; i < nbUncoveredBanks; i++) {
 			sections[SECTTYPE_ROMX].banks[i].sections = NULL;
 			sections[SECTTYPE_ROMX].banks[i].zeroLenSections = NULL;
 		}
-		sections[SECTTYPE_ROMX].nbBanks = nbOverlayBanks;
+		sections[SECTTYPE_ROMX].nbBanks = nbUncoveredBanks;
 	}
 }
 
@@ -195,16 +219,19 @@ static void writeROM(void)
 	outputFile = openFile(outputFileName, "wb");
 	overlayFile = openFile(overlayFileName, "rb");
 
-	checkOverlay();
+	uint32_t nbOverlayBanks = checkOverlaySize();
+
+	if (nbOverlayBanks > 0)
+		coverOverlayBanks(nbOverlayBanks);
 
 	if (outputFile) {
 		if (sections[SECTTYPE_ROM0].nbBanks > 0)
 			writeBank(sections[SECTTYPE_ROM0].banks[0].sections,
-				  0x0000, 0x4000);
+				  startaddr[SECTTYPE_ROM0], maxsize[SECTTYPE_ROM0]);
 
 		for (uint32_t i = 0 ; i < sections[SECTTYPE_ROMX].nbBanks; i++)
 			writeBank(sections[SECTTYPE_ROMX].banks[i].sections,
-				  0x4000, 0x4000);
+				  startaddr[SECTTYPE_ROMX], maxsize[SECTTYPE_ROMX]);
 	}
 
 	closeFile(outputFile);

src/linkdefs.c

@@ -13,11 +13,11 @@ uint16_t startaddr[] = {
 };
 
 uint16_t maxsize[] = {
-	[SECTTYPE_ROM0]  = 0x8000,
+	[SECTTYPE_ROM0]  = 0x8000, // patched to 0x4000 if !is32kMode
 	[SECTTYPE_ROMX]  = 0x4000,
 	[SECTTYPE_VRAM]  = 0x2000,
 	[SECTTYPE_SRAM]  = 0x2000,
-	[SECTTYPE_WRAM0] = 0x2000,
+	[SECTTYPE_WRAM0] = 0x2000, // patched to 0x1000 if !isWRA0Mode
 	[SECTTYPE_WRAMX] = 0x1000,
 	[SECTTYPE_OAM]   = 0x00A0,
 	[SECTTYPE_HRAM]  = 0x007F