226 Chapter 40. VAX Dependent FeaturesThe -h n option determines how we map names. This takes several values. No -h switch at allallows case hacking as described above. A value of zero (-h0) implies names should be uppercase, and inhibits the case hack. A value of 2 (-h2) implies names should be all lower case, withno case hack. A value of 3 (-h3) implies that case should be preserved. The value 1 is unused.The -H option directs as to display every mapped symbol during assembly.Symbols whose names include a dollar sign $ are exceptions to the general name mapping. Thesesymbols are normally only used to reference VMS library names. Such symbols are alwaysmapped to upper case.-+The -+ option causes as to truncate any symbol name larger than 31 characters. The -+ optionalso prevents some code following the _main symbol normally added to make the object filecompatible with Vax-11 "C".-1This option is ignored for backward compatibility with as version 1.x.-HThe -H option causes as to print every symbol which was changed by case mapping.40.2. VAX Floating PointConversion of flonums to floating point is correct, and compatible with previous assemblers. Roundingis towards zero if the remainder is exactly half the least significant bit.D, F, G and H floating point formats are understood.Immediate floating literals (e.g. S‘$6.9) are rendered correctly. Again, rounding is towards zero inthe boundary case.The .float directive produces f format numbers. The .double directive produces d format num-bers.40.3. Vax Machine DirectivesThe Vax version of the assembler supports four directives for generating Vax floating point constants.They are described in the table below..dfloatThis expects zero or more flonums, separated by commas, and assembles Vax d format 64-bitfloating point constants..ffloatThis expects zero or more flonums, separated by commas, and assembles Vax f format 32-bitfloating point constants.
