!lm12
!rm75
Correction

Last month I described the BIT instruction incorrectly.  The next to the last paragraph on page 2 (in "Run-Anywhere Subroutine Calls") should read:

!lm+5
!rm-5
The BIT instruction copies bit 7 of $FF58 into the N-status  bit, and bit 6 into the Overflow status bit.  This, in other words (since $FF58 has $60 in it) clears N and sets Overflow.
!lm-5
!rm+5

BIT does not affect Carry Status in any way.  BIT also sets or clears the Z-status bit, according to the value of the logical product of the A-register and the addressed byte.  If you want Z and/or N to be flags to the calling program, you will have to modify them after the BIT instruction.


Another Customizing Patch for the S-C Macro Assembler

Version 4.0 of the S-C Assembler stopped after any assembly error.  Many users requested that I modify it to continue to the end of assembly, and display the error count at the end.  So I did.

Now some users are requesting that I change it back.  They walk away during assembly, and the error messages scroll off the screen.  (But you can put .LIST OFF at the beginning, and then only the error lines will list.)

There is a very simple patch for this.  The byte at $1D6F ($DD6F in the language card version) is now $18.  Change it $38 and assembly will stop after the first error message.


Subscription Renewals

If your address label shows a number 8209 or smaller in the upper right corner, it is time to renew.  That is $15 bulk mail in the USA; $18 First Class in USA, Canada, and Mexico; $28 to other countries.


New Macro Cross Assemblers Available

The high cost of dedicated microprocessor development systems has forced many technical people to look for alternate methods to develop programs for the various microprocessors.  Combining your very versatile Apple II with the S-C Macro Assembler provides a cost effective and powerful development system.

There are now three cross-assembler modules ready for the S-C Macro Assembler, and more to come.  Each cross-assembler disk costs $32.50 to registered owners of the S-C Macro Assembler.  You get both regular and language card versions, with documentation of the special features and differences.

The 6809 cross-assembler is designed to work with the Stellation Mill.  The MGO command starts the 6809 processor executing your assembled object code.  Likewise, the Z-80 version is designed to work with the Microsoft Softcard.

We have begun working on a Motorola 68000 version....
