From 3b46e7ef1f4c3f364e75e780eff923ef146ee42c Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Sat, 23 Jun 2018 15:12:55 -0400
Subject: Implement initial builtin commands

---
 builtin_free.asm | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 builtin_free.asm

(limited to 'builtin_free.asm')

diff --git a/builtin_free.asm b/builtin_free.asm
new file mode 100644
index 0000000..96e3c86
--- /dev/null
+++ b/builtin_free.asm
@@ -0,0 +1,35 @@
+%ifndef _BUILTIN_FREE_ASM
+%define _BUILTIN_FREE_ASM
+
+builtin_free:
+	push bp
+	mov bp, sp
+
+	mov cx, word [bp + 4]	; argc
+	mov bx, word [bp + 6]	; argv
+
+	;cmp cx, 0		; if no arguments, return
+	;jbe .return
+
+	mov ah, 88h		; get extended memory size
+	int 15h
+	mov dx, ax
+
+	int 12h			; get conventional memory size
+				; but it's pretty much bogus
+
+	push dx
+	push ax
+	push .msg_fmt
+	call printf
+	add sp, 2 * 2
+	add bx, 2
+
+	.return:
+		mov sp, bp
+		pop bp
+		ret
+	.msg_fmt db 'Conventional memory: %dK\n'
+		 db 'Extended memory: %dK', 0
+
+%endif
-- 
cgit