Undocumented command line options for BC.EXE (QuickBASIC 4.0)


/AM and /AL

I believe these, along with the documented /AH, set the amount of memory
allowed for arrays. /AL is the default setting. It's possible that the M,
L and H stand for MEDIUM, LARGE and HUGE.

BC internal representation - /AM = 0
/AL = 1
/AH = 2

Default value is 1.

/T

Not known just what this one does yet. It DOES do something.


/FPA, /FPC, /FPC87, /FPI and /FPI87

/FPI is default. Changes the way floating-point routines are called within
your program. In my testing, /FPA, /FPC and /FPC87 all created an OBJ
module that needed an external library linked with it. The "C" appears to
stand for "CALL" while the "I" stands for "INTERRUPT". I haven't figured
out what the "A" stands for. By the way, BC does notice the difference
between /FPC and /FPC87 (likewise with /FPI and /FPI87). I haven't figured
out what the differences in output are yet. None of the machines I have
available for testing have the 80x87 and that may be important in this
case.

BC internal representation - /FPA = 0
/FPC = 2
/FPC87 = 3
/FPI = 4
/FPI87 = 5

Default value is 4.

===========================================================================

Noticeable differences between /FPC and /FPI

PRINT ATN(1) * 4 'calculated value for PI (3.14159)

With /FPI:

int 35 ;FLD dword ptr [0040]
int 3D ;FWAIT
call B$ATN4
int 34 ;FMUL dword ptr [0044]
sub sp,4
mov bx,sp
int 35 ;FSTP dword ptr [BX]
int 3D ;FWAIT
call B$PER4
call B$CENP

With /FPC:

mov bx,0040
call __flds ;FLD dword ptr [0040]
call B$ATN4
mov bx,0044
call __fmuls ;FMUL dword ptr [0044]
sub sp,4
mov bx,sp
call __fstsp ;FSTP dword ptr [BX]
call B$PER4
call B$CENP

===========================================================================

Please send any comments to Michael Addy [74017,2437]. If it can be
determined exactly what these options do (instead of relying on my
guesswork), I will revise this file.