218-223



     ($FFFF) to the BASIC program (low byte in 212, high byte in
     213). The floating point package, if used, requires all locations
     from 212 to 255. All six bytes of FR0 can be used by a machine
     language routine, provided FR0 isn't used and no FP functions
     are used by that routine. To use 16 bit values in FP, you would
     place the two bytes of the number into the least two bytes of FR0
     (212, 213; $D4, $D5), and then do a JSR to $D9AA (55722), which
     will convert the integer to its FP representation, leaving the result
     in FR0. To reverse this operation, do a JSR to $D9D2 (55762).

218-223        DA-DF          FRE
     FP extra register (?)

224-229        E0-E5          FR1
     Floating point register one; holds a six-byte internal form of the
     FP number as does FR0. The FP package frequently transfers
     data between these two registers and uses both for two-number
     arithmetic operations.

230-235        E6-EB          FR2
     FP register two.

236            EC             FRX
     FP spare register.

237            ED             EEXP
     The value of E (the exponent).

238            EE             NSIGN
     The sign of the FP number.

239            EF             ESIGN
     The sign of the exponent.

240            F0             FCHRFLG
     The first character flag.

241            Fl             DIGRT
     The number of digits to the right of the decimal.

242            F2             CIX
     Character (current input) index. Used as an offset to the input
     text buffer pointed to by INBUFF below.

243,244        F3,F4          INBUFF
     Input ASCII text buffer pointer; the user's program line input
     buffer, used in the translation of ATASCII code to FP values. The
     result output buffer is at locations 1408 to 1535 ($580 to $5FF).

245,246        F5,F6          ZTEMP1
     Temporary register.