move findfreeiocb function into its own object file

2013-06-25 01:12:11 +02:00
parent c4c67b9205
commit 1bd902787b
3 changed files with 30 additions and 26 deletions
--- a/libsrc/atari/findfreeiocb.inc
+++ b/libsrc/atari/findfreeiocb.inc
@@ -0,0 +1,23 @@
+; find a free iocb
+; no entry parameters
+; return ZF = 0/1 for not found/found
+;        index in X if found
+; all registers destroyed
+
+.proc   findfreeiocb
+
+        ldx     #0
+        ldy     #$FF
+loop:   tya
+        cmp     ICHID,x
+        beq     found
+        txa
+        clc
+        adc     #$10
+        tax
+        cmp     #$80
+        bcc     loop
+        inx                     ; return ZF cleared
+found:  rts
+
+.endproc        ; findfreeiocb