X-Git-Url: http://git.dujemihanovic.xyz/projects?a=blobdiff_plain;f=kernel%2Fentry.s;h=a02df92d4703df4ada20654b433158c80ee1373f;hb=668fa121eb74d3317a73c2289f8805aaf1c84d7e;hp=236b81e967e459e4c6f684d137726dbf42743677;hpb=c9f2bccb44c5437f1cae0862b2c84d3af47eade8;p=nameless-os.git

diff --git a/kernel/entry.s b/kernel/entry.s
index 236b81e..a02df92 100644
--- a/kernel/entry.s
+++ b/kernel/entry.s
@@ -1,5 +1,12 @@
-	bits 32
-	extern _start
+; when our kernel source has functions before _start and we blindly transfer control to the beginning
+; of the kernel binary, it will wrongly execute the other functions
+; the solution is to link a small assembly routine (this) which executes a known label within the kernel
+; so that this routine comes before the kernel in the resulting binary
+; we cannot link the boot sector code and the kernel because the former needs to be a raw binary, while the
+; kernel is compiled into an ELF object file which contains some metadata on the kernel code
 
-	call _start
-	jmp $
+	bits 32 ; this is started in protected mode
+	extern _start ; the known label in the kernel source we will execute is, well, not in this assembly routine
+
+	call _start ; call the known label
+	jmp $ ; it should never return, but hang forever if it does