Here is an examplethat uses PRINTN macro:include 'emu8086.inc'ORG 100hMOV AL, 1MOV BL, 2PRINTN 'Hello World!'MOV CL, 3PRINTN 'Welcome!'RET macro.
#Negate bx in emu8086 code#
For example:memory, immediateň086 instructions of 53REG, immediatememory, REGREG, SREGzSome examples contain macros, so it is advisable to use Shift + F8 hot key to StepOver (to make macro code execute at maximum speed set step delay to zero),otherwise emulator will step through each instruction of a macro. For example:AL, DLDX, AXm1 DB ?AL, m1m2 DW ?AX, m2zSome instructions allow several operand combinations. Forexample:REG, memoryzWhen there are two operands, both operands must have the same size (except shiftand rotate instructions). I would recommend that you write 圆4 assembly codes (usually in a Linux system), and use the standard C library (for example _printf and _scanf functions) for I/O as the best replacement of INT 21H services.8086 instructions of 53Complete 8086 instruction setQuick reference:AAAAADAAMAASADCADDANDCALLCBWCLCCLDCLICMCCMPCMPSBCMPSWCWDDAADASDECDIVHLTIDIVIMULININCINTINTOIRETJAJAEJBJBEJCJCXZJEJGJGEJLJLEJMPJNAJNAEJNBJNBEJNCJNEJNGJNGEJNLJNLEJNOJNPJNSJNZJOJPJPEJPOJSJZLAHFLDSLEALESLODSBLODSWLOOPLOOPELOOPNELOOPNZLOOPZMOVMOVSBMOVSWMULNEGNOPNOTOROUTPOPPOPAPOPFPUSHPUSHAPUSHFRCLRCRREPREPEREPNEREPNZREPZRETRETFROLRORSAHFSALSARSBBSCASBSCASWSHLSHRSTCSTDSTISTOSBSTOSWSUBTESTXCHGXLATBXOROperand types:REG: AX, BX, CX, DX, AH, AL, BL, BH, CH, CL, DH, DL, DI, SI, BP, SP.SREG: DS, ES, SS, and only as second operand: CS.memory:, , variable, etc.(see Memory Access).immediate: 5, -24, 3Fh, 10001101b, etc.Notes:zWhen two operands are required for an instruction they are separated by comma. But, if you could correct an issue in my code, I can tell you that you can easily go to the next step. Since then, I didn’t write code for MS-DOS (or its emulator) any more, and unfortunately, I do not have access to either a true MS-DOS system or its emulator at the moment and therefore, I cannot test the issue and your code at the moment.
#Negate bx in emu8086 license#
I wrote this code using Emu86 (if I remember the name correctly) with a limited short-time license about 10 years ago. I think that this issue is specific to your emulator context and environment. Before this happens, the OS would handle all the BS keys properly and would prepare the ultimate string at the moment the key is pressed. That implies that the OS handles BS properly, and the ultimate string is not available to the code until the user hits the key. I am not convinced that (BS) is an issue in a true MS-DOS environment. bx: base register), but it doesn’t really matter. I found an issue at the moment of pressing backspace, bx kept increasing Get_fin: mov byte ptr, 0 terminate string with 0 Get_str: read string terminated by CR into array Mov al, byte ptr al = next char in string Mov al, byte ptr al = first char in string Msg1 db ‘Enter your favourite colour: ‘, 0Ĭall put_str display colour entered by user It just reduces the readability of the codeĮnd start set entry point and stop the assembler. bx: base register), but it doesn't really matter. si as base address (Names si: source index, It is a bit funny because I used BX as index and In return, CX would have the number of bytes actually read. DX contains the address of buffer in memory that would force the MS-DOS I/O to terminate the printing. The input string may not contain a $ character because The buffer must have 3 more rooms to save the (the maximum character to read) is in CX register. for unsigned integer: -1 is assumed 65535. value 3187, this function call itself (printud) prints the value of AX register in unsigned printd again for the quotient, and then we if the quotient is not zero, we first call print 5, we add '0' to it to make it '5'. In ASCII format, we should add '0' to it. DX contains the remainder, but since DX < 10 if quotient is zero, then print remainder if negative value, print - and call again with -value printd is called for the negate of value. If the value is negative, a - is printed then If the value to print is less than 10, then it is value 3187, this function call itself (printd) This function uses a recursive algorithm to print prints the value of AX register in signed call getstr to read a string from keyboard 3 extra places to store return/new-line and '$' The size of buffer is an adjustable constant A new-line (return character) would mark characters from keyboard, and prints it back. This program reads a string of at most 32 This program reads a string from keyboard and prints it back.