Differences

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--- inline_basic_assembler [2025/06/19 15:22] – [Writing a Program] reggie
+++ inline_basic_assembler [2025/06/20 10:17] (current) – [Dragon Basic Inline Assembler] reggie
@@ Line 1: / Line 1: @@
 ====== Dragon Basic Inline Assembler ======
-This utility (GTAsm) is intended for small 6809 machine language utilities that enhance programs written mostly in Dragon Basic, for example a routine to scroll the graphics screen. The assembly source code is written in Basic comment statements.
+This utility (GTAsm) is intended for developing small 6809 machine language routines that enhance programs written mostly in Dragon Basic, for example a routine to scroll the graphics screen. The assembly source code is written in Basic comment statements. This documentation assumes a good working knowledge of the 6809 and the Dragon 32.
 [[https://6809.uk/cas/GTAsm.cas|Download GTAsm Inline Basic Assembler]] (as a .cas file for the Dragon 32 - get the [[https://www.6809.org.uk/xroar/|XRoar Emulator]])
@@ Line 38: / Line 38: @@
 Or, since we used the DEFUSR1 directive:
-  A=USR1(0)
+  A=USR01(0)
 EXEC remembers its last address, so as long as we don't use it (or DEFUSR0) for something else we can type plain EXEC to re-run the assembler.
@@ Line 51: / Line 51: @@
   TFR (use TRF instead - this is a simple error)
+=== Addressing ===
+Use standard brackets rather than square to specify indirect addressing. Use the "<" and ">" symbols to force 8 and 16 bit offsets respectively.
+  JSR (,X++)        call subroutine at address stored at X, then point to the next address in the list
+  LDA (CURSPOS)     load A from the address stored at CURSPOS
+  LDB >$0034        load B from $0034 using extended mode rather than direct
+  CLR <LINELEN,Y    clear the byte at Y+LINELEN, forcing 8 bit offset mode (doesn't work!)
 === Directives ===