alex.buell's articles:

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It lives! 0 24 (5/9/2011 2:55:31 PM) comp.lang.asm.x86 I have now succeeded in transitioning from RM to PM and back again. I hereby place the following program in the public domain. You will need NASM to compile it as a .COM file: nasm -fbin -o dos32.com dos32.asm ... Freedom

Still having trouble transitioning from PM to RM :( 0 23 (5/8/2011 7:32:01 PM) comp.lang.asm.x86 Can someone cast their eye over this code and see what the problem with it is? It's still failing to transition to RM from PM through a far jmp which has been patched with the correct CS segment. Perhaps there ... Freedom

JMPs not working in protected mode? 5 35 (5/5/2011 1:48:23 PM) comp.lang.asm.x86 Hi,=20 As some of you might know, I've been experimenting with protected mode under MS-DOS. However, whilst getting into protected mode has been successful, I can't figure out why making JMPs whilst in protect... Freedom

Patch for alink 1.6. to build under Linux 0 29 (5/1/2011 8:37:19 AM) comp.lang.asm.x86 I hereby place this patch in the public domain; ports alink 1.6 to Linux. My previous port of alink to Linux in 2005 wasn't quite right.=20 Patch as follows: diff -uNr alink-1.6/alink3.mak alink/alink3.mak --... Freedom

Dumping registers 1 25 (4/29/2011 11:01:49 AM) comp.lang.asm.x86 I present here a program to print out the values in the registers. Comments and optimisations all welcome. This is real mode only but it will be used to print out registers whilst in protected mode at some poin... Freedom

Odd problem with int 0x21, ah = 0x4A 49 39 (4/28/2011 2:18:19 PM) comp.lang.asm.x86 I have the following applet: BITS 16 ORG 0x100 =20 mov ax, ss mov dx, es sub ax, dx mov bx, sp shr bx, 4 add bx, ax mov ah, 0x4A int 0x21 ret In the debugger, all segment registers all point to the... Freedom

nasm equivalents? 2 31 (4/27/2011 11:27:22 PM) comp.lang.asm.x86 What's the NASM equivalent of 'or eax, 1 shl 8' (MASM?) Thanks! --=20 Tactical Nuclear Kittens ... Freedom

Booting grub-enabled binary images 8 33 (4/21/2011 10:55:28 PM) comp.lang.asm.x86 I have a protected mode binary that books just fine with grub, but crashes'n'burn with my own bootloader. Does anyone knows what a grub-enabled binary image needs to boot?=20 My bootloader is a multistage boot... Freedom

Protected mode bootloader question 11 35 (8/10/2010 9:18:36 AM) comp.lang.asm.x86 What if the assembler or the linker is unable to correctly generate the correct offset i.e. no OFFSET 0x7c00? How would the programmer ensure that the bootloader set up the segment registers and references to v... Alex

NASM - Recursive Macros and Beyond! 9 90 (8/7/2010 11:38:10 AM) comp.lang.asm.x86 Whilst we're on the subject, I recently patched NASM 2.08.01 to compile and run under MS-DOS, where should I send my patches? I had to rename some files to fit MS-DOS 8.3 file name size limits, please do adhere... Alex

alex.buell's replies:

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Pseudo random numbers / DOS / memory, etc.... 74 76 (10/30/2011 3:47:31 PM) comp.lang.asm.x86 Hi I am a newbie, and I have made a program that generates some pseudo=20 random numbers, and print how many times each number come out.=20 I have two problems;=20 1. I am not sure the dynamic memory alloca... lianergoist (7)

Could someone figure out why the below code is not working? 24 30 (7/7/2011 5:39:55 AM) comp.lang.asm.x86 Hello All, The below is simple code to a sentence to 'titlised'. ..section .data ..equ EMPTY, ' ' ..equ FIRSTCH, 'a' ..equ LASTCH, 'z' ..equ CONVERSION, 'A' - 'a' ..equ END, '0' mystring: ..ascii "hello world0... emekamicro1 (17)

SVGA in DOS vs. Windows 7 33 (6/12/2011 11:36:14 PM) comp.lang.asm.x86 My SVGA (VBE 1.2 compatible) program runs well in DOS. With the same hardware, but with Windows XP, it does not. Can someone explain? Thanks. D. Baruth ... google5187 (4)

Weird error with floppy image booting Kernel? 34 32 (5/28/2011 11:36:48 AM) comp.lang.asm.x86 [30208 May 28 12:33 kernel.sys] : This is the number of bytes that is _allowed_ with my boot loader. When I 'nop' the kernel to 30209 bytes or higher, the virtual machine resets. Why is this? My Operating Syst... obrzut.alex (64)

Re: print 1 character in linux... #4 2 24 (5/10/2011 8:13:28 AM) comp.lang.asm.x86 On Monday, May 9, 2011 4:04:07 PM UTC-4, robert...@yahoo.com wrote: > > Also, I'm curious how AT&T's syntax pre-dated Intel's, when they > > made the chip? > > The AT&T syntax has been used on many ISAs. Obvi... foxmuldrster (53)

Re: JMPs not working in protected mode? 2 37 (5/6/2011 7:31:04 AM) comp.lang.asm.x86 On Friday, May 6, 2011 1:05:25 AM UTC-5, Rod Pemberton wrote: > Are you trying to switch back to real mode here? Typically, one wants to > reload CS and DS with, AIUI..., 16-bit PM selectors with base 0, segmen... foxmuldrster (53)

Odd problem with int 0x21, ah = 0x4A 49 39 (4/28/2011 2:18:19 PM) comp.lang.asm.x86 I have the following applet: BITS 16 ORG 0x100 =20 mov ax, ss mov dx, es sub ax, dx mov bx, sp shr bx, 4 add bx, ax mov ah, 0x4A int 0x21 ret In the debugger, all segment registers all point to the... alex.buell (44)

nasm equivalents? 2 31 (4/27/2011 11:27:22 PM) comp.lang.asm.x86 What's the NASM equivalent of 'or eax, 1 shl 8' (MASM?) Thanks! --=20 Tactical Nuclear Kittens ... alex.buell (44)

Booting grub-enabled binary images 8 33 (4/21/2011 10:55:28 PM) comp.lang.asm.x86 I have a protected mode binary that books just fine with grub, but crashes'n'burn with my own bootloader. Does anyone knows what a grub-enabled binary image needs to boot?=20 My bootloader is a multistage boot... alex.buell (44)

What is INT 21 used for? 14 25 (3/12/2011 5:34:22 PM) comp.lang.asm.x86 I've recently started writing 16 bit real mode code, and I am completely confused about INT 21. So far, every book and web site I have found says that INT 21 is a DOS service, yet if I call this function withou... lloydjatkinson (3)