x86-16

I am learning Operating system tutorials. I created 2 files. boot.asm kernel.c The kernel.c is as follows : int main() { char *src = (char *)0xB8000000L; *src = 'M'; src += 2; *src = 'D'; return 0; } The kernel is used to write a character to the text mode video display area. The kernel was compiled using Windows version of GCC with: gcc -ffreestanding -c -m16 kernel.c -o kernel.o I link the kernel object to a binary file using LD : ld -Ttext 0x10000 --oformat binary -o kernel.bin kernel.o The error I get is: ld : cannot link the file which is not PE executable type Can anybody solve this

I have a little 8086 emulator and I've had a long standing bug for like 2 years now that AF does not behave properly inside of sub and add instructions. My current way of computing its value is this for 8 bit numbers and subtraction: uint8_t base=... , subt=... base=base&0xF; subt=subt&0xF; //isolate bottom nibble if((int16_t)base-subt>7 || (int16_t)base-subt<-7){ flags.af=1; }else{ flags.af=0; } (assuming an instruction like sub base,subt ) And for adding it's like this: uint8_t base=... , adder=... base=base&0xF; adder=adder&0xF; //isolate bottom nibble if(base+adder>7 || base+adder<-7){

When I use ADC for exmaple: AL = 01 and BL = 02, and CF = 1 when I make this: ADC AL,BL Will AL be 3 or 4 ? (with the CF addition or without?) Few things about the 8086 ADC instruction: Syntax: adc dest, src dest: memory or register src: memory, register, or immediate Action: dest = dest + src + CF Clearly the action says the Carry Flag ( CF ) will be included in the addition so the result will be 4 not 3 . It is no different than adding in base 10. 99 +11 9+1 is zero carry the 1 9+1+carry is 1 carry the 1 The result of the above decimal math is 10 with a carry of 1, or 110 if you want to

im working on a assembly program that reads the whole text file into a buffer then displays it in the console. It displays 24 lines (each line has a max lenght of 80, because im using a 80 wide * 25 height dossbox ) at once then waits for user input so the user can scroll through the text. I wanted to add the number of line to the beginning of each line, so figured i could make a second buffer and copy chars 1by1 from the first one and when i find a newline i would call a procedure which would add the line number to the buffer, then continue till i proceed thru the whole buffer. But my way of

I am writing some little tools for MS-DOS. Now I'm writing a Shutdown.com , like for Windows XP and greater. I have already written the entire code, now I just need to pass the argument from DOS. I need to pass the parameters "-r" to reboot and "-s" to shutdown. How can I do it? I'm using TASM(Turbo Assembler 4.1) on Windows 98 to link and compile. I'm looking for a very simple way to do it, and if possible, still a .COM program. I'm looking exactly like the ARGV and ARGC from C language, but for Assembly 16-bits... shutdown -r will reboot shutdown -s will shutdown Remember that I already know