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--- base:runasmfrombasic [2017-07-28 12:26] – Simple stub. pararaum
+++ base:runasmfrombasic [2017-07-28 12:53] (current) – Fixed typo. pararaum
@@ Line 48: / Line 48: @@
 As can be easily seen the SYS to address 2064 starts the code at $0810.
+==== Fancier ways to call the Assembler code ====
+=== Using the current line number ===
+This is the canonical way to call an Assembler code. Usually you precalculate the entry or you have to be very careful when changing the basic stub. Another nice way to call the assembler code is the following stub:
+  	.word $0801
+  	* = $0801
+  basic:	.(
+  	.word end_of_basic
+  	.word main
+  	.byte $9e,$20,$c2
+  	.asc "(57)",$aa,"256",$ac,$c2,"(58)"
+  end_of_basic:
+  	.byte 0,0,0
+  	.)
+  main:	lda #$0d
+  	sta $d020
+      	rts
+This code uses the zeropage locations $39/$3A which contain the current line number in the basic program, see [[https://www.c64-wiki.com/wiki/zeropage|zeropage description]]. The line number was selected to be the entry of the main routine.
+=== Using ASC() ===
+If you like to get your code fancier you can use something like this:
+  	.word $0801
+  	* = $0801
+  basic:	.(
+  	.word L1
+  	.word main
+  	.byte $9e
+  	.asc "(",$c6,"(",$22
+  	.byte ((main>>6)&$3f)+$20
+  	.asc $22,")",$ab,"32)",$ac,"64",$aa,$c6,"(",$22
+  	.byte ((main)&$3f)+$20
+  	.asc $22,")",$ab,"32"
+  	.asc 0
+  L1:	.word end_of_basic
+  	.word L1
+  	.byte $8f,$20
+  	.asc "ANOTHER VISITOR STAY A WHILE...",0
+  end_of_basic:
+  	.word 0,0
+  	.)
+  main:	lda #$0d
+  	sta $d020
+       	rts
+This use two characters to encode the starting address (maximum is 4096). The basic code actually reads:
+SYS(ASC("A")-32)*64+ASC(")")-32
+REM ANOTHER VISITOR STAY A WHILE...
+The line numbers are even not ordered but this code safely runs.