From 260db9f8d7f031d16176b22f0554511ac6222afe Mon Sep 17 00:00:00 2001
From: Ain <41307858+nero@users.noreply.github.com>
Date: Sat, 23 Mar 2019 20:17:47 +0000
Subject: [PATCH] Move kernel libs into subdir, create NBP-specific entrypoint

---
 Makefile                          |  8 +++++---
 debug.asm => kernel/debug.asm     |  0
 kernel/heap.asm                   | 28 ++++++++++++++++++++++++++++
 intr.asm => kernel/intr.asm       |  0
 kprintf.asm => kernel/kprintf.asm |  0
 main.asm => nbp.asm               | 24 ++++++++++--------------
 run.sh                            |  4 ++--
 7 files changed, 45 insertions(+), 19 deletions(-)
 rename debug.asm => kernel/debug.asm (100%)
 create mode 100644 kernel/heap.asm
 rename intr.asm => kernel/intr.asm (100%)
 rename kprintf.asm => kernel/kprintf.asm (100%)
 rename main.asm => nbp.asm (72%)

diff --git a/Makefile b/Makefile
index 8c5399b..32e8d85 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,7 @@
-kernel.com: *.asm
-	nasm -s -o kernel.com main.asm
+default: nbp.com
+
+%.com: %.asm
+	nasm -s -o $@ $<
 
 clean:
-	rm -f kernel.com
+	rm -f *.com
diff --git a/debug.asm b/kernel/debug.asm
similarity index 100%
rename from debug.asm
rename to kernel/debug.asm
diff --git a/kernel/heap.asm b/kernel/heap.asm
new file mode 100644
index 0000000..a25cdf6
--- /dev/null
+++ b/kernel/heap.asm
@@ -0,0 +1,28 @@
+heap_size:
+  dw 0x0100
+
+heap_init:
+  push ax ; byte value (0)
+  push cx ; loop counter
+  push di ; target ptr
+  xor ax, ax
+  mov cx, [heap_size]
+  mov di, heap
+  rep stosb ; rep makes this loop cx times, incrementing di, writing al
+  pop di
+  pop cx
+  pop ax
+  ret
+
+; in	ax	number of bytes to alloc
+; out	ds:di
+malloc:
+  push dx ; length of block index
+  or ax,0x0F
+  inc ax
+  mov dx, 0x100
+  mov bp, heap
+
+  int 0x2E
+  pop dx
+  ret
diff --git a/intr.asm b/kernel/intr.asm
similarity index 100%
rename from intr.asm
rename to kernel/intr.asm
diff --git a/kprintf.asm b/kernel/kprintf.asm
similarity index 100%
rename from kprintf.asm
rename to kernel/kprintf.asm
diff --git a/main.asm b/nbp.asm
similarity index 72%
rename from main.asm
rename to nbp.asm
index c6386ce..69eca89 100644
--- a/main.asm
+++ b/nbp.asm
@@ -1,6 +1,6 @@
 ; assumptions about the starting envionment
 cpu 8086
-org 0x0000 ;	if we are not at CS:0000, CS adjustment will fix it for us
+org 0x0000
 ; dl		probable drive number
 ; ds:si		probable pointer to partition structure
 ; es:bx		probable pxeenv+ structure
@@ -42,28 +42,24 @@ _exit:
 main:
   mov ax, cs
   mov ds, ax
+  mov es, ax
 
   mov bx, 0x002E
   mov dx, debug_reg_ir
 
   call ivt_set
 
-  mov ax, 0
-  mov bx, 0
-  call cons
-  mov si, di
-  call print
+  call heap_init
+  mov ax, 18
+  call malloc
 
   ret
 
-%include "intr.asm"
-%include "debug.asm"
-%include "kprintf.asm"
-%include "heap.asm"
-
-%include "cons.asm"
-%include "int.asm"
-%include "print.asm"
+%include "kernel/heap.asm"
+%include "kernel/intr.asm"
+%include "kernel/debug.asm"
+%include "kernel/kprintf.asm"
 
+align 16
 heap:
   dw 0
diff --git a/run.sh b/run.sh
index 1bd108f..8d144c3 100755
--- a/run.sh
+++ b/run.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-exec qemu-system-x86_64 -boot n \
+exec qemu-system-x86_64 -boot n -fda fd0.img \
 	-option-rom /usr/share/qemu/pxe-rtl8139.rom \
 	-device e1000,netdev=mynet0,mac=52:54:00:12:34:56 \
-	-netdev user,id=mynet0,net=192.168.76.0/24,dhcpstart=192.168.76.9,tftp=$PWD,bootfile=kernel.com
+	-netdev user,id=mynet0,net=192.168.76.0/24,dhcpstart=192.168.76.9,tftp=$PWD,bootfile=nbp.com