mobygamer's articles:

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Is this operation atomic? 7 50 (9/20/2012 3:44:18 AM) comp.lang.asm.x86 I'm finishing up a total rewrite of an interrupt-heavy program (the previous version was a nightmare of pushf/cli/popf wrapping to prevent race conditions in code shared by multiple interrupt handlers -- don'... Jim

Possible to change flags without math op? 25 57 (7/11/2012 7:21:05 PM) comp.lang.asm.x86 I'm writing a piece of code for real-mode 16-bit x86 that needs to process a sequence of bytes and do something with their values based on whether or not they are 00, FF, or neither. Jumping based on the ze... Jim

Possible to emulate PUSH imm16 on 808x? 28 40 (4/1/2012 12:45:38 AM) comp.lang.asm.x86 I'm trying to make changes to a 286-specific size-optimized program to get it to compile and run on 8088/8086 and have written macros for things like PUSHA/POPA and SHR reg,imm8, but I ran across a PUSH imm16 a... Jim

Nybble access in real mode 17 44 (1/11/2012 3:24:25 PM) comp.lang.asm.x86 (reposting as it seems it was sent to the bit bucket a few days ago) I apologize in advance for what might be a stupid question, but is there any faster way to access/prepare the high nybble in an 8-bit regist... Jim

UMOV opcode removal 3 43 (12/30/2011 3:50:23 PM) comp.lang.asm.x86 I was trying to use a CPU detection routine that relied on the undocumented UMOV instruction to differentiate between AMD 386sx and Intel 386sx chips, but testing that routine has found it flawed (ie. everythin... Jim

Opcode frequency process/tools? 23 33 (10/26/2011 6:41:38 PM) comp.lang.asm.x86 Regarding Rod Pemberton's post on opcode frequency and how it pertains to emulator optimization ( http://groups.google.com/group/comp.lang.asm.x86/msg/cb3ce37f449a0074 ), I was wondering if anyone knew of a pro... Jim

Looking for confirmation on HLT behavior 7 39 (10/7/2011 2:16:42 PM) comp.lang.asm.x86 I've written code to test this but just want a second opinion, since the Intel manual wasn't *explicitly* clear: It's my understanding that when a HLT pauses the CPU, and then an interrupt fires, the CPU servi... Jim

Best assembler/workflow for this 16-bit project? 44 148 (1/17/2011 4:49:21 PM) comp.lang.asm.x86 As a hobby exercise, I will be developing a somewhat large program for a very ancient 808x computer with limited RAM (128KB). So far, most of my projects in this realm have been in Turbo Pascal 7.0 with a m... Jim

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Persistent memory during reset 8 42 (11/30/2011 8:44:51 PM) comp.lang.asm.x86 Is there any standard region of BIOS or x86 platform memory that persists after a system reset. I need to store a counter value (a byte would be enough) that persists during system reset, but is obviously clear... adrian.maxwell.smith (1)

Fast and small Multiplicative Random number generator 81 71 (12/19/2011 1:08:24 PM) comp.lang.asm.x86 Hi everybody, some days ago i started thinking upon a fast and simple random number generator of few lines of codes, wondering about the use of MUL and RDTSC. after some "deviations" from the theory :-) i stum... hopcode5394 (42)

UMOV opcode removal 3 43 (12/30/2011 3:50:23 PM) comp.lang.asm.x86 I was trying to use a CPU detection routine that relied on the undocumented UMOV instruction to differentiate between AMD 386sx and Intel 386sx chips, but testing that routine has found it flawed (ie. everythin... mobygamer (60)

Nybble access in real mode 17 44 (1/11/2012 3:24:25 PM) comp.lang.asm.x86 (reposting as it seems it was sent to the bit bucket a few days ago) I apologize in advance for what might be a stupid question, but is there any faster way to access/prepare the high nybble in an 8-bit regist... mobygamer (60)

Reading IP for a program monitor 3 39 (1/20/2012 8:27:26 PM) comp.lang.asm.x86 Every few years, I get the idea in my head that it would be cute/ interesting to write a DOS TSR that would display CS:IP in the top corner of the screen, so you could watch the numbers fly by, see if your lock... MobyGamer301 (139)

Dump memory from ISR 61 56 (3/13/2012 9:53:43 PM) comp.lang.asm.x86 Hi guys, I have a problem and wanna know if anyone has some ideas about it. I need to dump the entire memory (about 1gb) to a file from a ISR. I assume I can=B4t do it in real mode, right? So first problem... pgerotica (10)

Possible to emulate PUSH imm16 on 808x? 28 40 (4/1/2012 12:45:38 AM) comp.lang.asm.x86 I'm trying to make changes to a 286-specific size-optimized program to get it to compile and run on 8088/8086 and have written macros for things like PUSHA/POPA and SHR reg,imm8, but I ran across a PUSH imm16 a... mobygamer (60)

Replacing single byte in doubleword 13 39 (4/18/2012 3:29:19 PM) comp.lang.asm.x86 Is there a smart non-SIMD way of replacing a single byte in a doubleword, let's say a comma by a space or an asterisk by a zero, other than a loop, like mov ecx, 4 @1: cmp al, "," ; or whatever ... spamtrap14 (66)

Possible to change flags without math op? 25 57 (7/11/2012 7:21:05 PM) comp.lang.asm.x86 I'm writing a piece of code for real-mode 16-bit x86 that needs to process a sequence of bytes and do something with their values based on whether or not they are 00, FF, or neither. Jumping based on the ze... mobygamer (60)

Is this operation atomic? 7 50 (9/20/2012 3:44:18 AM) comp.lang.asm.x86 I'm finishing up a total rewrite of an interrupt-heavy program (the previous version was a nightmare of pushf/cli/popf wrapping to prevent race conditions in code shared by multiple interrupt handlers -- don'... mobygamer (60)