From f39f25a4c1aa56b2678bd1c94237125eb115d812 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juhani=20Krekel=C3=A4?= <juhani@krekelä.fi>
Date: Sat, 18 Mar 2023 01:05:32 +0200
Subject: [PATCH] Start work on shell

---
 Makefile    |  6 ++++--
 ponydos.asm | 11 +++++++++++
 shell.asm   |  2 ++
 3 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 shell.asm

diff --git a/Makefile b/Makefile
index 50c28b6..8b0de76 100644
--- a/Makefile
+++ b/Makefile
@@ -6,8 +6,10 @@ PYTHON = python3
 
 all: ponydos.img
 
-ponydos.img: ponydos.bin wallpaper.bin
-	$(PYTHON) assemble_floppy.py $@ ponydos.bin wallpaper.bin
+FS_FILES = wallpaper.bin shell.bin
+
+ponydos.img: ponydos.bin $(FS_FILES)
+	$(PYTHON) assemble_floppy.py $@ ponydos.bin $(FS_FILES)
 
 .asm.bin:
 	$(NASM) -fbin -o $@ $<
diff --git a/ponydos.asm b/ponydos.asm
index 30bab61..499c273 100644
--- a/ponydos.asm
+++ b/ponydos.asm
@@ -71,6 +71,16 @@ load_wallpaper:
 	call read_sectors
 	; TODO: error management? Surely this works...
 
+load_shell:
+	mov ax, 0x1000
+	mov es, ax
+	mov si, shell_name
+	call open_file
+	xor bx, bx
+	call read_sectors
+
+	call 0x1000:0
+
 initialize_screen:
 	; Disable text cursor
 	mov ah, 0x01
@@ -226,6 +236,7 @@ modify_sector:
 ; ------------------------------------------------------------------
 
 wallpaper_name: db 'wallpaper.bin', 0
+shell_name: db 'shell.bin', 0
 
 ; in:
 ;  ds:si = file name
diff --git a/shell.asm b/shell.asm
new file mode 100644
index 0000000..dfd51d1
--- /dev/null
+++ b/shell.asm
@@ -0,0 +1,2 @@
+org 0
+retf