core: add decimal number write routine

Add routine to write decimal numbers, currently unused, but likely to
become useful at some time or another.

diff --git a/core/writedec.inc b/core/writedec.inc
new file mode 100644 (file)
index 0000000..235943d
--- /dev/null
+++ b/core/writedec.inc
@@ -0,0 +1,56 @@
+;; -----------------------------------------------------------------------
+;;
+;;   Copyright 1994-2008 H. Peter Anvin - All Rights Reserved
+;;
+;;   This program is free software; you can redistribute it and/or modify
+;;   it under the terms of the GNU General Public License as published by
+;;   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+;;   Boston MA 02111-1307, USA; either version 2 of the License, or
+;;   (at your option) any later version; incorporated herein by reference.
+;;
+;; -----------------------------------------------------------------------
+
+;;
+;; writedec.inc
+;;
+;; Write decimal numbers to the console
+;;
+
+               section .text
+;
+; writedec[bwl]: Write a hex number in (AL, AX, EAX) to the console
+;
+writedecb:
+               pushad
+               movzx eax,al
+               jmp short writedec_common
+writedecw:
+               pushad
+               movzx eax,ax
+               jmp short writedec_common
+writedecl:
+               pushad
+writedec_common:
+               pushfd
+               mov ebx,10              ; Conversion base
+               xor cx,cx               ; Number of digits
+
+.cloop:
+               div ebx
+               inc cx
+               push dx
+               and eax,eax
+               jnz .cloop
+
+.dloop:
+               pop ax
+               add al,'0'
+               call writechr
+               loop .dloop
+
+               popfd
+               popad
+               ret
+
+writechr:
+               ret