From d173f81cd6c91a80f46fd1f34922a9155adebcdf Mon Sep 17 00:00:00 2001
From: "E. Almqvist" <elalmqvist@gmail.com>
Date: Wed, 13 Apr 2022 12:14:36 +0200
Subject: [PATCH] Minor refactor

---
 bootloader/bios/memory.asm | 40 ++++++++++++++++++++------------------
 bootloader/bootloader.asm  | 14 ++++++-------
 2 files changed, 28 insertions(+), 26 deletions(-)

diff --git a/bootloader/bios/memory.asm b/bootloader/bios/memory.asm
index 4f41588..0d96434 100644
--- a/bootloader/bios/memory.asm
+++ b/bootloader/bios/memory.asm
@@ -1,19 +1,19 @@
 ; SRs to find memory size and leave it as a "note" for the kernel
 
-mmap_probe:		; literally just test the memory boundaries
-	push eax
-	push ebx
-	push edx
-	push ebp
-
-	mov ebp, esi
-	add esi, 0x00000ff
-	and esi, ~0x00000ff
-mmap_probe_addr:
-
-mmap_probe_done:
-
-mmap_e820:
+; mmap_probe:		; literally just test the memory boundaries
+; 	push eax
+; 	push ebx
+; 	push edx
+; 	push ebp
+; 
+; 	mov ebp, esi
+; 	add esi, 0x00000ff
+; 	and esi, ~0x00000ff
+; mmap_probe_addr:
+; 
+; mmap_probe_done:
+
+e820:
 	mov di, 0x8004
 	mov ebx, 0	; Must be 0 
 	mov bp, 0	; entry count
@@ -27,15 +27,17 @@ mmap_e820:
 	int 0x15					; Do the interupt
 
 	; carry flag = (un)supported function
-	jc mmap_e820_fail			; Try probing instead
+	jc e820_fail			; Try probing instead
 
 	cmp eax, edx				; eax should be = 'SMAP'
-	jne mmap_e820_fail			; if not then fail
+	jne e820_fail			; if not then fail
+
+	test ebx, ebx				; no entries
+	je e820_fail
+
 
-	test ebx, ebx
-	je mmap_e820_fail
 
-mmap_e820_fail:
+e820_fail:
 	stc
 	ret
 
diff --git a/bootloader/bootloader.asm b/bootloader/bootloader.asm
index 91112b7..35a05c3 100644
--- a/bootloader/bootloader.asm
+++ b/bootloader/bootloader.asm
@@ -35,15 +35,15 @@
 ; Switching to PM
 [bits 16]
 pm_preinit:
-	call mmap_e820	; Map the physical memory
-
-	cli			; Switch interupts
+	; Do stats before mode switch
+	call e820				; Map the physical memory
 
+	; PM prep stuff
+	cli						; Switch interupts
 	lgdt [gdt_descriptor] 	; Tell the CPU about the GDT
-
-	mov eax, cr0		; Set first bit of the CR0 register
-	or eax, 0x1			; to 1
-	mov cr0, eax		; Update the control register
+	mov eax, cr0			; Set first bit of the CR0 register
+	or eax, 0x1				; to 1
+	mov cr0, eax			; Update the control register
 
 	; Initialize PM
 	jmp GDT_CODE_SEG:pm_init