diff --git a/include/link/output.h b/include/link/output.h
index 7c43d2c3..0cf531c6 100644
--- a/include/link/output.h
+++ b/include/link/output.h
@@ -14,8 +14,15 @@
 
 #include "link/section.h"
 
+/**
+ * Registers a section for output.
+ * @param section The section to add
+ */
 void out_AddSection(struct Section const *section);
 
+/**
+ * Writes all output (bin, sym, map) files.
+ */
 void out_WriteFiles(void);
 
 #endif /* RGBDS_LINK_OUTPUT_H */
diff --git a/src/link/assign.c b/src/link/assign.c
index 5fa70b35..4780e120 100644
--- a/src/link/assign.c
+++ b/src/link/assign.c
@@ -104,6 +104,15 @@ static inline void assignSection(struct Section *section,
 	out_AddSection(section);
 }
 
+/**
+ * Checks whether a given location is suitable for placing a given section
+ * This checks not only that the location has enough room for the section, but
+ * also that the constraints (alignment...) are respected.
+ * @param section The section to be placed
+ * @param freeSpace The candidate free space to place the section into
+ * @param location The location to attempt placing the section at
+ * @return True if the location is suitable, false otherwise.
+ */
 static bool isLocationSuitable(struct Section const *section,
 			       struct FreeSpace const *freeSpace,
 			       struct MemoryLocation const *location)
@@ -118,6 +127,13 @@ static bool isLocationSuitable(struct Section const *section,
 					<= freeSpace->address + freeSpace->size;
 }
 
+/**
+ * Finds a suitable location to place a section at.
+ * @param section The section to be placed
+ * @param location A pointer to a location struct that will be filled
+ * @return A pointer to the free space encompassing the location, or NULL if
+ *         none was found
+ */
 static struct FreeSpace *getPlacement(struct Section const *section,
 				      struct MemoryLocation *location)
 {
@@ -177,9 +193,16 @@ static struct FreeSpace *getPlacement(struct Section const *section,
 		location->bank++;
 		if (location->bank > bankranges[section->type][1])
 			return NULL;
+#undef BANK_INDEX
 	}
 }
 
+/**
+ * Places a section in a suitable location, or error out if it fails to.
+ * @warning Due to the implemented algorithm, this should be called with
+ *          sections of decreasing size.
+ * @param section The section to place
+ */
 static void placeSection(struct Section *section)
 {
 	struct MemoryLocation location;
@@ -293,6 +316,12 @@ struct UnassignedSection {
 static struct UnassignedSection *unassignedSections[1 << 3] = {0};
 static struct UnassignedSection *sections;
 
+/**
+ * Categorize a section depending on how constrained it is
+ * This is so the most-constrained sections are placed first
+ * @param section The section to categorize
+ * @param arg Callback arg, unused
+ */
 static void categorizeSection(struct Section *section, void *arg)
 {
 	(void)arg;
diff --git a/src/link/object.c b/src/link/object.c
index 28c7633e..3585f64e 100644
--- a/src/link/object.c
+++ b/src/link/object.c
@@ -145,6 +145,12 @@ static char *readstr(FILE *file)
 
 /***** Functions to parse object files *****/
 
+/**
+ * Reads a RGB6 symbol from a file.
+ * @param file The file to read from
+ * @param symbol The struct to fill
+ * @param fileName The filename to report in errors
+ */
 static void readSymbol(FILE *file, struct Symbol *symbol, char const *fileName)
 {
 	tryReadstr(symbol->name, file, "%s: Cannot read symbol name: %s",
@@ -171,6 +177,13 @@ static void readSymbol(FILE *file, struct Symbol *symbol, char const *fileName)
 	}
 }
 
+/**
+ * Reads a RGB6 patch from a file.
+ * @param file The file to read from
+ * @param patch The struct to fill
+ * @param fileName The filename to report in errors
+ * @param i The number of the patch to report in errors
+ */
 static void readPatch(FILE *file, struct Patch *patch,
 		      char const *fileName, char const *sectName, uint32_t i)
 {
@@ -201,6 +214,12 @@ static void readPatch(FILE *file, struct Patch *patch,
 	patch->rpnExpression = rpnExpression;
 }
 
+/**
+ * Reads a RGB6 section from a file.
+ * @param file The file to read from
+ * @param section The struct to fill
+ * @param fileName The filename to report in errors
+ */
 static void readSection(FILE *file, struct Section *section,
 			char const *fileName)
 {
@@ -266,6 +285,11 @@ static void readSection(FILE *file, struct Section *section,
 	}
 }
 
+/**
+ * Links a symbol to a section, keeping the section's symbol list sorted.
+ * @param symbol The symbol to link
+ * @param section The section to link
+ */
 static void linkSymToSect(struct Symbol const *symbol, struct Section *section)
 {
 	uint32_t a = 0, b = section->nbSymbols;
@@ -290,6 +314,11 @@ static void linkSymToSect(struct Symbol const *symbol, struct Section *section)
 	section->nbSymbols++;
 }
 
+/**
+ * Reads a RGB6 object file.
+ * @param file The file to read from
+ * @param fileName The filename to report in errors
+ */
 static void readRGB6File(FILE *file, char const *fileName)
 {
 	uint32_t nbSymbols;
@@ -378,6 +407,10 @@ static void readRGB6File(FILE *file, char const *fileName)
 	}
 }
 
+/**
+ * Reads an object file of any supported format
+ * @param fileName The filename to report for errors
+ */
 void obj_ReadFile(char const *fileName)
 {
 	FILE *file = strcmp("-", fileName) ? fopen(fileName, "rb") : stdin;
diff --git a/src/link/output.c b/src/link/output.c
index 81605c2b..6f99e66e 100644
--- a/src/link/output.c
+++ b/src/link/output.c
@@ -73,6 +73,9 @@ void out_AddSection(struct Section const *section)
 	*ptr = newSection;
 }
 
+/**
+ * Performs sanity checks on the overlay file.
+ */
 static void checkOverlay(void)
 {
 	if (!overlayFile)
@@ -88,6 +91,9 @@ static void checkOverlay(void)
 	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 (nbOverlayBanks < 1)
@@ -104,6 +110,12 @@ static void checkOverlay(void)
 	}
 }
 
+/**
+ * Write a ROM bank's sections to the output file.
+ * @param bankSections The bank's sections, ordered by increasing address
+ * @param baseOffset The address of the bank's first byte in GB address space
+ * @param size The size of the bank
+ */
 static void writeBank(struct SortedSection *bankSections, uint16_t baseOffset,
 		      uint16_t size)
 {
@@ -141,6 +153,9 @@ static void writeBank(struct SortedSection *bankSections, uint16_t baseOffset,
 	}
 }
 
+/**
+ * Writes a ROM file to the output.
+ */
 static void writeROM(void)
 {
 	checkOverlay();
@@ -164,6 +179,12 @@ static void writeROM(void)
 	}
 }
 
+/**
+ * Get the lowest section by address out of the two
+ * @param s1 One choice
+ * @param s2 The other
+ * @return The lowest section of the two, or the non-NULL one if applicable
+ */
 static struct SortedSection const **nextSection(struct SortedSection const **s1,
 						struct SortedSection const **s2)
 {
@@ -175,6 +196,10 @@ static struct SortedSection const **nextSection(struct SortedSection const **s1,
 	return (*s1)->section->org < (*s2)->section->org ? s1 : s2;
 }
 
+/**
+ * Write a bank's contents to the sym file
+ * @param bankSections The bank's sections
+ */
 static void writeSymBank(struct SortedSections const *bankSections)
 {
 	if (!symFile)
@@ -236,6 +261,10 @@ static void writeSymBank(struct SortedSections const *bankSections)
 #undef sect
 }
 
+/**
+ * Write a bank's contents to the map file
+ * @param bankSections The bank's sections
+ */
 static void writeMapBank(struct SortedSections const *sectList,
 			 enum SectionType type, uint32_t bank)
 {
@@ -276,6 +305,9 @@ static void writeMapBank(struct SortedSections const *sectList,
 			slack == 1 ? "" : "s");
 }
 
+/**
+ * Writes the sym and/or map files, if applicable.
+ */
 static void writeSymAndMap(void)
 {
 	if (!symFile && !mapFile)
diff --git a/src/link/patch.c b/src/link/patch.c
index bc86fb06..255a7f7a 100644
--- a/src/link/patch.c
+++ b/src/link/patch.c
@@ -69,6 +69,12 @@ static uint8_t getRPNByte(uint8_t const **expression, int32_t *size,
 	return *(*expression)++;
 }
 
+/**
+ * Compute a patch's value from its RPN string.
+ * @param patch The patch to compute the value of
+ * @param section The section the patch is contained in
+ * @return The patch's value
+ */
 static int32_t computeRPNExpr(struct Patch const *patch,
 			      struct Section const *section)
 {
@@ -272,6 +278,11 @@ static int32_t computeRPNExpr(struct Patch const *patch,
 	return popRPN();
 }
 
+/**
+ * Applies all of a section's patches
+ * @param section The section to patch
+ * @param arg Ignored callback arg
+ */
 static void applyPatches(struct Section *section, void *arg)
 {
 	(void)arg;
diff --git a/src/link/script.c b/src/link/script.c
index 0f499370..1f5880ad 100644
--- a/src/link/script.c
+++ b/src/link/script.c
@@ -21,6 +21,13 @@ static inline bool isNewline(int c)
 	return c == '\r' || c == '\n';
 }
 
+/**
+ * Try parsing a number, in base 16 if it begins with a dollar,
+ * in base 10 otherwise
+ * @param str The number to parse
+ * @param number A pointer where the number will be written to
+ * @return True if parsing was successful, false otherwise
+ */
 static bool tryParseNumber(char const *str, uint32_t *number)
 {
 	static char const digits[] = {