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Text File | 1985-08-11 | 14.6 KB | 518 lines | [TEXT/Anon]

MAC.68K IF IF IF PURPOSE To conditionally assemble or skip source lines based on an attribute test. FORMAT IF attribute,expression IF -attribute,expression ifname IF attribute,expression ifname IF -attribute,expression IF attribute,expression,lcnt IF -attribute,expression,lcnt ifname IF attribute,expression,lcnt ifname IF -attribute,expression,lcnt attribute TRUE if DEF All symbols in expression are defined. AREG Expression is an address register direct. DREG Expression is a data register direct. IREG Expression is an indirect register reference. ABS Expression is an absolute memory reference. PREL Expression is a program relative reference. SREG Expression is a status register. IMMD Expression is immediate data. DESCRIPTION IF tests an expression for an attribute and begins assembling the IF block if the test is true, or begins skipping if the test is not true. By using a - prefix on the attribute type, the effect of the test is reversed. The IF block is either bounded by ELSE/ENDC pseudo op codes, or is a specified line count in length. If the line count parameter lcnt is used, the following source lines are skipped until either the count is exhausted, or until an unnamed ELSE or a named ELSE with a matching ifname is found. If a count is not specified, the IF block is terminated by an unnamed ENDC or a matching named ENDC. Within the block the effects of the test may be reversed by an unnamed ELSE or an ELSE with a matching ifname. By using named IF blocks, a virtually unlimited amount of conditional nesting may occur. -37- MAC.68K MAC.68K IFS / IFC IFS / IFC IFS / IFC PURPOSE To conditionally skip or assemble source lines based on string comparisons. FORMAT IFS comparision,dstring1dstring2d IFS comparision,dstring1dstring2d,lcnt ifname IFS comparision,dstring1dstring2d ifname IFS comparision,dstring1dstring2d,lcnt comparison EQ NE GE GT LE LT d String delimiter character. Any character not occuring in string 1 or in string 2 except for & or ". string Character strings to compare lcnt Optional source line skip count DESCRIPTION IFS compares two strings and begins assembly if the comparison is true, or begins skipping source lines if the comparison is false. The comparison is done left to right until the condition is found false or the strings are exhausted. A short string is logically padded with null characters. The IF block is either bounded by ELSE/ENDC pseudo op codes, or is a specified line count in length. If the line count parameter lcnt is used, the following source lines are skipped until either the count is exhausted, or until an unnamed ELSE or a named ELSE with a matching ifname is found. If a count is not specified, the IF block is terminated by an unnamed ENDC or a matching named ENDC. Within the block the effects of the test may be reversed by an unnamed ELSE or an ELSE with a matching ifname. By using named IF blocks, a virtually unlimited amount of conditional nesting may occur. The pseudo ops IFC and IFNC are recognized and processed as the equivalent IFS pseudo ops. Their format is the same as described by AS68. EXAMPLE RETURN MACRO ADDR IFS EQ,*ADDR** TEST FOR NULL PARAMETER RTS ELSE BRA ADDR ENDC ENDM MAC.68K -38- MAC.68K IFxx IFxx IFxx PURPOSE To conditionally assemble or skip source lines based on a comparison of two expressions. FORMAT IFxx expression1 IFxx expression1,expression2 IFxx expression1,expression2,lcnt ifname IFxx expression1,expression2 ifname IFxx expression1,expression2,lcnt xx EQ NE GE GT LE LT lcnt Optional source line skip count. DESCRIPTION IFxx compares two expressions and begins assembly if the xx condition is true, or begins skipping if the xx condition is false. If expression2 is not present, expression1 is compared to zero. Any symbols used in the expressions must be previously defined. The IF block is either bounded by ELSE/ENDC pseudo op codes, or is a specified line count in length. If the line count parameter lcnt is used, the following source lines are skipped or assembled until either the count is exhausted, or until an unnamed ELSE or a named ELSE with a matching ifname is found. If a count is not specified, the IF block is terminated by an unnamed ENDC or a matching named ENDC. Within the block the effects of the test may be reversed by an unnamed ELSE or an ELSE with a matching ifname. By using named IF blocks, a virtually unlimited amount of conditional nesting may occur. EXAMPLES IFGT PAGSIZE,24 BSR ADVANP ELSE BSR ADVANL FOO IFLE BAZ,BAZLIMIT,3 BSR SETBAZ FOO ENDC ENDC -39- MAC.68K MAC.68K INCLUDE INCLUDE INCLUDE PURPOSE To insert text from another file into the assembly. FORMAT INCLUDE filename DESCRIPTION INCLUDE reads in all the text from the specified file name and MAC.68K then assembles that text before resuming assembly with the next line of input. INCLUDE may be nested to 5 levels. MAC.68K uses a default extension of blanks. EXAMPLES INCLUDE IODECKS.TXT INCLUDE B:IODECKS MAC.68K -40- MAC.68K INCLUDEH INCLUDEH INCLUDEH PURPOSE To load a previously assembled object module. FORMAT INCLUDEH filename DESCRIPTION INCLUDEH reads in a previously assembled .MOD file. MAC.68K adds the current value of the location counter to any entry point symbol values from the .MOD file and enters the symbol names in the symbol table. MAC.68K then inserts the object code from the .MOD file at the current origin counter and advances the origin and location counters by the length of the object code. MAC.68K uses a default extension of .MOD. EXAMPLE INCLUDEH RUNIO -41- MAC.68K MAC.68K INCLUDES INCLUDES INCLUDES PURPOSE To load a previously assembled set of symbols and macro definitions. FORMAT INCLUDES filename INCLUDES filename,symbol,symbol,...symbol DESCRIPTION INCLUDES is an initialization directive. It must appear after the IDENT card but before any non-initialization operation codes. INCLUDES reads a previously assembled .STX file and enters the symbols and macros from the .STX file into the current symbol and macro tables. A maximum of three INCLUDES may be used in one assembly. In the case of duplicate symbol or macro definitions, the first one encountered is used. MAC.68K uses a default extension of .STX . A list of symbol names that are NOT to be defined may appear after the filename. This allows the program to define its own values for those symbols. EXAMPLES INCLUDES CPMTEXT INCLUDES CPMTEXT,FCBL MAC.68K -42- MAC.68K LIST LIST LIST PURPOSE To select which lines are written to the list file. FORMAT LIST option1,option2,...optionN Default Option Line type controlled by option - A Image prior to concatenation and string substitution. - C Op codes: PAGE SPACE TITLE and SUBTTL. - D DUPlicated lines. - E DEFERed lines. - F IF skipped lines. - G M68000 instructions and data op codes. Overrides LIST options M and S. - I Included text lines. + L All source lines. - M User macro expansions. - S System macro expansions. $ All options. * Reinstate options in effect prior to previous LIST. DESCRIPTION LIST options are a single character or a single character prefixed by a -. Multiple options separated by commas may be used, and are scanned from left to right. A single character enables the option and the - prefix disables the option. Line types are inclusive in nature and all LIST options that apply must be selected before a source line is listed. For example, to list an IF skipped line within a user macro called in an included text file requires options L,I,M,F to be enabled. The prior list option is remembered and may be restored by using LIST *. LIST -$ will turn off all options. LIST G is useful for listing macro expansions. EXAMPLES LIST -L LIST L,F,-M LIST * -43- MAC.68K MAC.68K LOC LOC LOC PURPOSE To set the current location counter. FORMAT LOC expression DESCRIPTION The location counter is used to assign address values to location field symbols on M68000 instructions and data pseudo ops. It may be set independent of the origin counter. By default the location counter equals the origin counter, and a new ORG will also automatically reset the LOC counter. Caution is advised when changing the LOC because code generated with mismatching ORG and LOC values probably will not execute properly. All symbols used in the expression to generate the new LOC value must be previously defined. The current value of the location counter may be referenced by using the special symbols * or *L. Often used to assemble blocks of code to be moved at execution time from the ORGed address to the LOCed address. Also used for assembly of table definitions containing relative addresses (see also OFFSET). EXAMPLES LOC $FF0000 LOC *O Reset LOC to current origin address MAC.68K -44- eset LOC to current origin address MAC.68K