In qsort, make sure to do nothing if count is 0.

Previously, it could behave incorrectly in some cases where count was 0. This would happen if the address calculation &base[-1] wrapped around and produced a large number, either because base was NULL or because size was larger than the address of base. This fixes #33.
2021-02-25 22:52:34 -06:00 · 2021-02-25 22:52:34 -06:00 · 7e95f8b182
parent 9af245933c
commit 7e95f8b182
1 changed files with 4 additions and 1 deletions
--- a/stdlib.asm
+++ b/stdlib.asm
@ -663,6 +663,9 @@ qsort    start
         phk
         plb

+         lda   count                    nothing to do if count is 0
+         ora   count+2
+         beq   done
         dec4  count                    set count to the addr of the last entry
         mul4  count,size
         add4  count,base
@ -677,7 +680,7 @@ qsort    start
         ph4   base
         jsl   rsort

-         plb
+done     plb
         creturn
         end