Эмулятор процессора Intel 8086 версия 4.05 (ENG) / asm_files / fasm_compatibility.asm

source code: fasm_compatibility.asm a:link {text-decoration: none} a:visited {text-decoration: none} a:hover {text-decoration: none; color:#ff0000}     ; fasm_compatibility.asm ; Flat Assembler uses the Intel syntax. ; Effective for: ; Flat assembler version 1.64 ; emu8086 integrated assembler version 4.00-Beta-20 (or above) #fasm# ; this code is for fasm. org 100h name "fasmcomp" ; === [NOTE 1] ; calculate the sum of 'a' and 'b' jmp start a dw 5 b dw 7 start: ; this is correct syntax for emu8086 integrated assembler, ; but it is wrong for fasm: mov ax, a mov bx, b add ax, bx ; AX = offset a + offset b (AX=206) (correct, but not what we expect) ; correct syntax for fasm: mov ax, [a] mov bx, [b] add ax, bx ; AX = 5 + 7 (AX=000C) (correct) ;; to calculate sum of offsets for emu8086 integrated assembler ;; it is required to use the offset directive, for example: ; mov ax, offset a ; mov bx, offset b ; add ax, bx ; sum of offsets instead of values. ;; the offset directive is not supported for fasm (error: extra characters on line) ; Hello, World example in fasm: mov dx, msg mov ah, 9 int 21h ; for emu8086 integrated assembler: ; mov dx, offset msg ; or ; lea dx, msg ; (syntax of the integrated 8086 assembler is mostly MASM/TASM compatible) ; wait for any key... mov ah, 0 int 16h ret msg db "Hello, World!", 0x0D, 0x0A, "$" ; emu8086 compatible declaration is: ; msg: db "Hello, World!", 0x0D, 0x0A, "$" ; (note: there is ":" after msg) ; === [NOTE 2] ; fasm does not support the comment directive, for example: ; comment * ; la lalala la... ; * ; === [NOTE 3] ; these precompiler directives are preparsed by the IDE: ; NAME ; #make... ; #AX=... ; etc... ; === [NOTE 4] ; for fasm it's required to use "byte" and "word" prefixes ; in places where it may be required to use "byte ptr", "word ptr" ; or "b.", "w." prefixes for the integrated 8086 assembler. ; For example: mov byte [m1], AL m1 dw 1234h ; ; for the integrated 8086 assembler it should be: ; mov b. m1, AL ; ; or: ; mov byte ptr m1, AL ; (MASM compatible) ; === [NOTE 5] ; uninitialised variables are not added to actual binary file ; when these variables are located in the bottom of the file ; and there is no defined data after them (MASM compatible) ; 8086 assembler always initialises variables as 0 (MASM incompatibility) ; For example: u1 dw ? ; === [NOTE 6] ; fasm assembler is case sensitive; ; for example, the following code would cause ; "symbol redefinition" error for MASM or 8086 integrated assembler, ; but it is completely legal for fasm: mov [d], 9 mov [D], 12 ret d Dw 5 D dw 7 ; === [NOTE 7] ; there may be other slight syntax incompatibilities, ; if you find any problem feel free to email.

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