Fix some warnings in the decompressor and do not use special symbol main() for entry points

decompressor/Makefile

@@ -5,7 +5,7 @@ OBJCOPY = i386-elf-objcopy
 CFLAGS = -flto -Os -pipe -Wall -Wextra
 
 INTERNAL_CFLAGS =  \
-	-std=gnu99 \
+	-std=gnu11 \
 	-ffreestanding \
 	-fno-stack-protector \
 	-fno-pic \
@@ -32,7 +32,8 @@ INTERNAL_LDFLAGS = \
 .PHONY: all clean
 
 C_FILES := $(shell find ./ -type f -name '*.c' | sort)
-OBJ := $(C_FILES:.c=.o)
+ASM_FILES := $(shell find ./ -type f -name '*.asm' | sort)
+OBJ := $(ASM_FILES:.asm=.o) $(C_FILES:.c=.o)
 
 all: decompressor.bin
 
@@ -43,5 +44,8 @@ decompressor.bin: $(OBJ)
 %.o: %.c
 	$(CC) $(CFLAGS) $(INTERNAL_CFLAGS) -c $< -o $@
 
+%.o: %.asm
+	nasm $< -f elf32 -o $@
+
 clean:
 	rm -f decompressor.bin decompressor.elf $(OBJ)

decompressor/entry.asm

@@ -0,0 +1,18 @@
+extern bss_begin
+extern bss_end
+extern entry
+
+section .entry
+
+global _start
+_start:
+    cld
+
+    ; Zero out .bss
+    xor al, al
+    mov edi, bss_begin
+    mov ecx, bss_end
+    sub ecx, bss_begin
+    rep stosb
+
+    jmp entry

decompressor/linker.ld

@@ -1,5 +1,5 @@
 OUTPUT_FORMAT(elf32-i386)
-ENTRY(main)
+ENTRY(_start)
 
 SECTIONS
 {

decompressor/main.c

@@ -1,27 +1,11 @@
-asm (
-    ".section .entry\n\t"
-
-    "cld\n\t"
-
-    // Zero out .bss
-    "xor al, al\n\t"
-    "mov edi, OFFSET bss_begin\n\t"
-    "mov ecx, OFFSET bss_end\n\t"
-    "sub ecx, OFFSET bss_begin\n\t"
-    "rep stosb\n\t"
-
-    "mov ebx, OFFSET main\n\t"
-    "jmp ebx\n\t"
-);
-
 #include <stdint.h>
 #include <stddef.h>
 #include <gzip/tinf.h>
 
 __attribute__((noreturn))
-void main(uint8_t *compressed_stage2, size_t stage2_size, uint8_t boot_drive) {
+void entry(uint8_t *compressed_stage2, size_t stage2_size, uint8_t boot_drive) {
     // The decompressor should decompress compressed_stage2 to address 0x4000.
-    volatile uint8_t *dest = (volatile uint8_t *)0x4000;
+    uint8_t *dest = (uint8_t *)0x4000;
 
     tinf_gzip_uncompress(dest, compressed_stage2, stage2_size);
 

stage2/entry.asm

@@ -0,0 +1,18 @@
+extern bss_begin
+extern bss_end
+extern entry
+
+section .entry
+
+global _start
+_start:
+    cld
+
+    ; Zero out .bss
+    xor al, al
+    mov edi, bss_begin
+    mov ecx, bss_end
+    sub ecx, bss_begin
+    rep stosb
+
+    jmp entry

stage2/linker.ld

@@ -1,5 +1,5 @@
 OUTPUT_FORMAT(elf32-i386)
-ENTRY(main)
+ENTRY(_start)
 
 SECTIONS
 {

stage2/main.c

@@ -1,18 +1,3 @@
-asm (
-    ".section .entry\n\t"
-
-    "cld\n\t"
-
-    // Zero out .bss
-    "xor al, al\n\t"
-    "mov edi, OFFSET bss_begin\n\t"
-    "mov ecx, OFFSET bss_end\n\t"
-    "sub ecx, OFFSET bss_begin\n\t"
-    "rep stosb\n\t"
-
-    "jmp main\n\t"
-);
-
 #include <limine.h>
 #include <lib/term.h>
 #include <lib/real.h>
@@ -31,7 +16,7 @@ asm (
 #include <protos/chainload.h>
 #include <menu.h>
 
-void main(int boot_drive) {
+void entry(int boot_drive) {
     term_textmode();
 
     print("Limine " LIMINE_VERSION "\n\n");