ch6ex2.asm

a example for asm, for beginer to stady asm

			dat	SEGMENT
				    source_buffer	DB 48H
			dat	ENDS

			extra	SEGMENT
				    dest_buffer	DB 40 DUP(?)
			extra	ENDS

			code	SEGMENT
				    ASSUME	CS:code, DS:dat, ES:extra
		start:
					MOV		AX, dat
					MOV		DS, AX
					MOV		AX, extra			;CS不用赋值
					MOV		ES, AX
					
					MOV		AX, 06H
					MOV		BX, 34H
					CLC
					MOV		DX, AX
					SUB		AX, BX
					JC		AA
					MOV		DI, 2800H  ;物理地址为DS*16 + 2800
					AND		[DI], AX
					JMP		EE
				AA:	MOV		AX, DX
					SUB		BX, AX
					MOV		DI, 2800H
					MOV		[DI], BX

				EE:	MOV		AX, 4C00H
					INT		21H

				code	ENDS
					END start