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Q57891: How BC /G2 Option Makes Smaller .EXE Code in BASIC 7.00

Article: Q57891
Product(s): See article
Version(s): 7.00   | 7.00
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | | mspl13_basic
Last Modified: 2-FEB-1990

In Microsoft BASIC Professional Development System (PDS) Version 7.00
for MS-DOS and MS OS/2, the BC /G2 option generates code that is
specific to computers containing an 80286 processor chip. Code
generated with /G2 will run on computers with 80286 and 80386 chips,
but will not run on computers with 8086 or 8088 chips.

When compiled with the /G2 option, a program may be zero to ten
percent smaller. The percentage by which the size decreases is usually
more significant than the percentage by which the speed improves.

Note: The 80286 chip is also known as the 286, for short. The 80386 is
also known as the 386.

The biggest gain from the use of 286 instructions is the PUSH
immediate instruction. This is an operation frequently used by the
compiler. To get an idea of how many bytes you would save, compile an
existing program with the /A option and look for sequences of the
following:

   MOV     reg,constant
   PUSH    reg

These will be replaced with a single PUSH instruction, saving 1 or 2
bytes per instance.

We provided the BC /G2 option for developers who market their
compiled-BASIC products to customers with 286 or 386 machines.

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