Arjob Mukherjee coderarjob

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Software developer and electronic hobbyist. Interested in low level systems programming, FPGA, Operating System Development, Compilers, Vintage electronics.

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Bangalore, India
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coderarjob / Application program memory model of my OS

Last active August 4, 2019 16:32


	System calls will reside in the segment of the kernel or the device
	drivers. The caller function however can be on a different segment, and use
	to INT instruction to call any system call.

	Calling Convention:
	------------------

	A) Memory convention:
	Application programs (AP) in Megha have 'small' memory model: DS = SS

coderarjob / Assembly Rectified

Created July 28, 2019 21:16

	bits 16

	section .bss
	global _ch
	_ch:
	resb 1

	section .text
	global _main
	_main:

coderarjob / Listing (Wrong)

Created July 28, 2019 21:12

	bits 16

	section .bss
	global _ch
	_ch:
	resb 1

	section .text
	global _main
	_main:

coderarjob / Listing

Created July 28, 2019 17:35

Bruce's C compiler Source

	call start
	jmp short 0x3

	start:
	push bp
	mov bp,sp
	push di
	push si
	dec sp
	xor al,al

coderarjob / c_asm_main.c

Created July 28, 2019 15:36

	/* A sample file to demo the issues with compiling for a real mode 8086
	* environment*/

	asm(
	"call main\n\t"
	"jmp .\n\t"
	);

	#define SET_POS(r,c) (screenpos = r160 + c2)