# X65 Directives Directives are commands that control the assembler and include controls for conditional assembly, exporting multible binary files, creating linkable object files etc. The directives are case insensitive and can be preceeded by a dot .rept 8 { dc.b 1<: for example EVAL Current Address: * test_stack = 0 eval Checking referenced function, Should be 0: .referenced(test_stack) eval Checking defined function, Should be 1: .defined(test_stack) ### DC, DV Declare constant / Declare Value. The directive can be specific by appending .b for byte size, .w for word size, .t for triple size or .l for long size. The default size is 1 byte. Test: dc.b $20, *-Test ### BYTE, BYTES Same as dc.b ### WORD, WORDS Same as dc.w ### LONG Same as dc.l ### TEXT Add text to output, the order of characters can be changed with a string symbol, for instance: STRING FontOrder = " ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!#$%&*" TEXT [FontOrder] "HELLO #1!" ### INCLUDE Load and assemble another file at this address. ### INCBIN Load another file and include as binary data at this address. ### INCSYM Load symbols from a .sym file INCSYM "Main.Sym" Symbols can also be selected by a list on the same line: INCSYM InitMain, UpdateMain, ShutdownMain, "Main.Sym" ### INCDIR Add a folder to search for include files. ### IMPORT Generic version of INCLUDE, INCBIN with custom arguments ; include a raw binary file IMPORT "data.bin" IMPORT binary "data.bin" ; include a source file IMPORT source "defines.i" ; include a binary C64 file omitting the load address (first 2 bytes) IMPORT c64 "main.prg" ; include a text file IMPORT text "text.txt" IMPORT text petscii "petscii.txt" IMPORT text petscii_shifted "petscii.txt" IMPORT text "custom.txt" ; see TEXT directive Note that if the command line argument -xdefimp is used then IMPORT is equivalent to XREF instead. ### CONST Declare a symbol as const, assgning it again will cause an error. CONST VICBank = $4000 The constness of a symbol can be tested with the IFCONST directive or the CONST() eval function. ### LABEL Optional directive create a mutable label, a way to specify non-CONST. It has no actual function. ### STRING Declare a string symbol. Strings are a little bit limited but can be used for ordering characters in a TEXT declaration, or it can be used as assembler source. ; Some custom ordered text TEXT [FontOrder] "MAKE IT SO!" ; Macro for (x=start; x End { if (-1 == End) & (Start<129) string _ForEnd = "dex\nbpl _ForLoop" else string _ForEnd = "dex\ncpx #End\nbne _ForLoop" endif } else string _ForEnd = "" endif _ForLoop } macro forend { _ForEnd ; _ForEnd defined by a variation of the for macro undef _ForEnd undef _ForLoop } for.x(5, 1) lda buf1,x sta buf2,x forend ### UNDEF Remove a symbol like_bananas = 1 UNDEF like_bananas ### LABPOOL, POOL Create a pool of addresses to assign as labels dynamically. This acts as a linear stack allocator for temporary storage and is deallocated when the scope ends if declared as a local symbol. Pools can be defined as part of a larger pool. pool zpGlobal $40-$f8 ; all zero page usage zpGlobal pool zpLocal 16 ; temporary storage for regular functions zpGlobal pool zpUtility 16 ; temporary storage for utility functions zpGlobal pool zpInterrupt 8 ; temporary storage for interrupts zpGlobal pool zpBuffer 64 ; per module storage Allocate from a pool by using the pool name zpBuffer zpIntroTimer.w ; frame counter, 2 bytes zpBuffer zpScrollChar.8 ; 8 bytes of rol char for scroll { zpLocal .zpSrc.w ; 2 bytes source address zpLocal .zpDst.w ; 2 bytes dest address .. } ; at this point .zpSrc and .zpDst are deallocated and can be reused by other code. { zpLocal .zpCount ; 1 byte, same address as .zpSrc used above } ### IF Begin conditional code. Whatever lines follow will be assembled only if the expression following the IF evaluates to a non-zero value, the conditional block ends with ELSE, ELSEIF or ENDIF. conditional_code = 1 IF conditional_code ... ; this will be assembled because conditional_code is not zero ENDIF ### IFDEF, IFNDEF Similar to IF but only takes one symbol and the following lines will be assembled only if the symbol was defined previously (IFDEF) or not defined previously (IFNDEF) defined_symbol = 0 IFDEF defined_symbol ... ; this will be assembled because defined_symbol exists ENDIF ### IFCONST Similar to IF but like IFDEF only takes one symbol and the following lines will be assembled if the symbol is CONST. The symbol should be defined prior to testing it. CONST() is also an Eval Function that can be used to form more complex expressions using IF. IFCONST is equivalent to IF CONST() ### IFBLANK, IFNBLANK Checks if the argument exists, mostly for use in macros to test if an argument exists. BLANK() is also an Eval Function, IFBLANK is equivalent to IF BLANK(...) ### ELSE Requires a prior IF, the following line will be assembled only if the prior conditional block was not assembled. ELSE must be terminated by an ENDIF IF 1 lda #0 ELSE lda #2 ENDIF ### ELIF Requires a prior IF and allows another expression check before ending the conditional blocks IFDEF monkey lda #monkey_value ELIF DEFINED(zebra) lda #zebra_value ELSE lda #human_value ENDIF ### ENDIF Terminated a conditional segment of blocks. ### STRUCT Declare a set of labels offset from a base address. Example: STRUCT ArtSet { word ArtTiles word ArtColors word ArtMasks byte bgColor } Members of the structure can be referenced by the struct name dot member name: lda ArtSetData + ArtSet.bgColor ArtSetData: ds SIZEOF(ArtSet) ### ENUM Declare a set of incremental labels. Values can either be assigned or one more than the previous. The default first value is 0. enum PlayerIndex { None = -1, One, Two Three, Four, Count ; there are this many players } Enum values can be referenced by enum name dot value name: ldx #PlayerIndex.One { inx cpx #PlayerIndex.Count bcc ! } lda #PlayerIndex.Four ### REPT, REPEAT Repeats the code within { and } following the REPT directive and counter. Within the REPT code the symbol REPT has the current iteration count, starting at 0. const words = 10 .rept words * 2 { dc.b rept / 2 } If the command line option -endm is used then REPT uses ENDR instead of the braced scope so the equivalent to the above would be .rept words * 2 dc.b rept / 2 .endr ### A16, A8, XY16, XY8, I16, I8 Specific to 65816 assembly, controls the current accumulator and index register width (8 or 16 bits). Different assemblers use different names so various alternatives are allowed. ### DUMMY, DUMMY_END Creates a dummy section between DUMMY and DUMMY_END directives. ### DS, RES Define "section", Reserve. Reserves a number of bytes at the current address. The first argument is the number of bytes and the second argument is optional and is the byte to fill with. The main purpose is to reserve space in a BSS or ZP section. ### SCOPE, ENDSCOPE A specialized version of a scope, does the same this as a brace scope (code between { and }) but additionally marks all labels defined within as local. An unimplemented feature is that the scope can be named and then labels defined can be accessed outside the scope as ::