Makefile

@@ -1,31 +0,0 @@
-include config.mk
-
-.PHONY: build clean install uninstall masm mld msim
-
-build: masm mld msim
-	./bin/masm/masm -o ./bin/runtime.o ./lib/runtime.asm
-
-clean:
-	rm -fr ./bin
-
-install:
-	install -m 755 -D -t $(PREFIX)/bin ./bin/masm/masm
-	install -m 755 -D -t $(PREFIX)/bin ./bin/mld/mld
-	install -m 755 -D -t $(PREFIX)/bin ./bin/msim/msim
-	install -m 444 -D -t $(PREFIX)/lib/mips ./bin/runtime.o
-
-uninstall:
-	rm $(PREFIX)/bin/masm
-	rm $(PREFIX)/bin/mld
-	rm $(PREFIX)/bin/msim
-	rm $(PREFIX)/lib/mips/runtime.o
-	rmdir $(PREFIX)/lib/mips
-
-masm:
-	make -C ./masm build
-
-mld:
-	make -C ./mld build
-
-msim:
-	make -C ./msim build

README.md

@@ -6,17 +6,6 @@ a full mips r2000 toolchain with a assembler and linker
 
 outputs MIPS32r6 ELF32 Big Endian executables
 
-##### installing
-```bash
-$ make build
-$ sudo make install
-```
-
-##### uninstalling
-```bash
-$ sudo make uninstall
-```
-
 #### masm
 
 the assembler

compile_flags.txt

@@ -5,4 +5,3 @@
 -pedantic
 -Wno-gnu-binary-literal
 -Iinclude
--DPREFIX=/usr/local

config.mk

@@ -8,8 +8,6 @@ CFLAGS += -Wall -Wextra -pedantic
 CFLAGS += -Wno-initializer-overrides
 CFLAGS += -O0 -g
 
-PREFIX=/usr/local
-
 # ======================== CONFIG OPTIONS ==
 #
 # MAX LEX LENGTH

lib/runtime.asm

@@ -1,29 +0,0 @@
-#
-# MIPS32r6 ASSEMBLY RUNTIME
-# - sets up the stack
-# - calls main
-# - exits
-#
-
-.extern main
-
-.stack
-.align 2
-
-.space 4096
-__mips_stack:
-
-.text
-.align 2
-
-_start:
-	# setup stack
-	la $sp, __mips_stack
-
-	# call main
-	jal main
-
-	# exit
-	move $a0, $v0
-	li $v0, 1
-	syscall

mld/Makefile

@@ -4,6 +4,4 @@ SRC=.
 BIN=../bin/mld
 OUT=mld
 
-CFLAGS += -DPREFIX=$(PREFIX)
-
 include ../makefile.mk

mld/link.c

@@ -16,11 +16,8 @@
 
 static int load_objects(struct linker *linker)
 {
-	int max_entries = linker->args->in_count + 1;
-	// 1 needed for the runtime
-
 	linker->objects = malloc(sizeof(struct object) *
-			  max_entries);
+			  linker->args->in_count);
 	linker->obj_len = 0;
 
 	if (linker->objects == NULL) {
@@ -49,19 +46,6 @@ static int load_objects(struct linker *linker)
 skip_obj:
 	}
 
-	if (linker->args->freestanding == false) {
-		#define _STR(x) _STR2(x)
-		#define _STR2(x) #x
-
-		char *path = _STR(PREFIX) "/lib/mips/runtime.o";
-		struct object *obj = &linker->objects[linker->obj_len++];
-		if (object_load(obj, path))
-			return M_ERROR;
-
-		#undef _STR
-		#undef _STR2
-	}
-
 	return M_SUCCESS;
 }
 
@@ -177,7 +161,7 @@ static int relocate_symbol(struct linker *linker, struct object *obj,
 	struct segment *sec = NULL;
 	for (size_t i = 0; i < obj->phdr_len; i++) {
 		Elf32_Phdr *temp = &obj->phdr[i];
-		if (PHDR_SHDR_MATCH(temp, shdr)) {
+		if (shdr->sh_offset == temp->p_offset) {
 			sec = &obj->segments[i];
 			break;
 		}
@@ -402,22 +386,30 @@ static int relocate_instruction_rela(struct linker *linker,
 		return M_ERROR;
 	}
 	Elf32_Sym *sym = &symtab->syms[idx];
+	const char *symname = symtab->strtab->data + B32(sym->st_name);
 
-	char const *sym_name = symtab->strtab->data + B32(sym->st_name);
-	if (B32(sym->st_name) >= symtab->strtab->len) {
-		ERROR("relocation symbol name out of bounds");
-		return M_ERROR;
-	}
-
-	// get the new sym for the new vaddr
-	Elf32_Sym *new_sym = NULL;
-	if (symtab_get(&linker->symtab, &new_sym, sym_name)) {
-		ERROR("relocation symbol not found");
+
+	/// get the section header that the symbol is related to
+	Elf32_Shdr *shdr = NULL;
+	if (B16(sym->st_shndx) >= seg->obj->shdr_len) {
+		ERROR("shndx index [%d] out of bounds", B16(sym->st_shndx));
 		return M_ERROR;
 	}
+	shdr = &seg->obj->shdr[B16(sym->st_shndx)];
 
 	/// get the segment that the symbol is in
-	uint32_t sym_vaddr = B32(new_sym->st_value);
+	struct segment_table_entry *ent;
+	const char *segname = seg->obj->shstrtab->data + B32(shdr->sh_name);
+	if (B32(shdr->sh_name) >= seg->obj->shstrtab->len) {
+		ERROR("relocation segment name out of bounds");
+		return M_ERROR;
+	}
+	if (segtab_get(&linker->segments, &ent, segname)) {
+		ERROR("could not locate segment for relocation");
+		return M_ERROR;
+	}
+
+	uint32_t sym_vaddr = B32(sym->st_value) + ent->vaddr;
 	uint32_t *ins_raw = (uint32_t *) &seg->bytes[off];
 
 	union mips_instruction_data ins;
@@ -470,7 +462,7 @@ static int relocate_instruction_rela(struct linker *linker,
 	*ins_raw = B32(ins.raw);
 
 	if (warn)
-		WARNING("truncating relocation for symbol '%s'", sym_name);
+		WARNING("truncating relocation for symbol '%s'", symname);
 
 	return M_SUCCESS;
 
@@ -655,15 +647,6 @@ static int link_executable(struct linker *linker)
 	ehdr->e_shnum = B16(linker->shdr_len);
 	ehdr->e_shstrndx = B16(linker->shstrtab_shidx);
 
-	Elf32_Sym *entry = NULL;
-	if (symtab_get(&linker->symtab, &entry, "_start")) {
-		ERROR("undefined symbol _start");
-		return M_ERROR;
-	}
-
-	// BE to BE, no endiness conversion needed
-	ehdr->e_entry = entry->st_value;
-
 	update_offsets(linker);
 
 	if (write_file(linker))

mld/link.h

@@ -26,11 +26,6 @@
 #define ADDR_CHK(lnk_f, seg_f, max) \
 	((lnk_f) > max - (seg_f) || (lnk_f) + (seg_f) > max)
 
-// checks if a phdr and shdr are matches
-#define PHDR_SHDR_MATCH(phdr, shdr) (              \
-	((phdr)->p_offset == (shdr)->sh_offset) && \
-	((phdr)->p_filesz == (shdr)->sh_size))     \
-
 // start addresses for each tyoe of segment
 #define TEXT_VADDR_MIN 0x00400000
 #define DATA_VADDR_MIN 0x10000000
@@ -124,8 +119,6 @@ struct segment {
 
 	// object im related to
 	struct object *obj;
-	// segment table entry im related to
-	struct segment_table_entry *ent;
 
 	// relocation table
 	struct relocation_table reltab;
@@ -259,7 +252,6 @@ struct linker_arguments {
 	char **in_files;
 	int in_count;
 	char *out_file;
-	bool freestanding;
 };
 
 /* link object files */

mld/main.c

@@ -10,7 +10,6 @@ void help(void) {
 	printf("options:\n");
 	printf("\t-h\t\tprints this help message\n");
 	printf("\t-o <output>\tselect a output file destination\n");
-	printf("\t-f\t\tmake this binary freestanding (no runtime)\n");
 }
 
 int main(int argc, char **argv) {
@@ -19,12 +18,11 @@ int main(int argc, char **argv) {
 		.in_files = NULL,
 		.in_count = 0,
 		.out_file = "a.out",
-		.freestanding = false,
 	};
 
 	int c;
 
-	while ((c = getopt(argc, argv, "ho:f")) != 1) {
+	while ((c = getopt(argc, argv, "ho:")) != 1) {
 		switch(c) {
 		case 'h':
 			help();
@@ -32,9 +30,6 @@ int main(int argc, char **argv) {
 		case 'o':
 			args.out_file = optarg;
 			break;
-		case 'f':
-			args.freestanding = true;
-			break;
 		case '?':
 			return M_ERROR;
 		default:

mld/seg.c

@@ -31,9 +31,10 @@ static int load_shdr(struct object *obj, struct segment *seg, size_t index)
 		Elf32_Shdr *hdr = &obj->shdr[i];
 
 		// find shdr that matches  the offset in phdr
-		if (!PHDR_SHDR_MATCH(seg->phdr, hdr))
+		if (seg->phdr->p_offset != hdr->sh_offset)
 			continue;
 
+
 		// get name
 		uint32_t name = B32(hdr->sh_name);
 		if (name >= obj->shstrtab->len) {
@@ -42,6 +43,11 @@ static int load_shdr(struct object *obj, struct segment *seg, size_t index)
 		}
 		seg->name = &obj->shstrtab->data[name];
 
+		if (seg->phdr->p_filesz != hdr->sh_size) {
+			ERROR("segment phdr and shdr file sizes to not match");
+			return M_ERROR;
+		}
+
 		// map bytes
 		uint32_t len = B32(hdr->sh_size);
 		uint32_t off = B32(hdr->sh_offset);
@@ -148,7 +154,6 @@ int segment_load(struct object *obj, struct segment *seg, size_t index)
 	seg->align = B32(seg->phdr->p_align);
 
 	seg->obj = obj;
-	seg->ent = NULL;
 
 	return M_SUCCESS;
 }

mld/segtab.c

@@ -136,8 +136,6 @@ int segtab_ent_push(struct segment_table_entry *ent, struct segment *seg)
 	}
 
 	ent->parts[ent->len++] = seg;
-	seg->ent = ent;
-
 	return M_SUCCESS;
 }
 

msim/Makefile

@@ -1,7 +0,0 @@
-include ../config.mk
-
-SRC=.
-BIN=../bin/msim
-OUT=msim
-
-include ../makefile.mk

msim/main.c

@@ -1,5 +0,0 @@
-
-int main(void) {
-	// NOT YET IMPLEMENTED
-	return 1;
-}

test/masm/test.asm

@@ -18,6 +18,7 @@ null:
 .text
 .align 2
 .globl main
+.globl _start
 
 # init the heap
 heap_init:
@@ -203,6 +204,7 @@ realloc_free:
 	jr	$ra
 
 
+_start:
 main:
 	# push return address
 	addi	$sp, $sp, -4