Editing Sharp PC-1500 (section)

==BASIC compatibility with early models==
Some earlier model PC-1500s will show a value 1 less in the FOR...NEXT counter on exiting the loop compared to later PC-1500s and the PC-1600.<ref>Sharp PC-1600 Operation Manual, 1986, p.355.</ref>

For example:

<syntaxhighlight lang="basic">
10 FOR K=1 TO 10
20 NEXT K
30 PRINT K
</syntaxhighlight>

K will be set to 11 on later model PC-1500s and PC-1600s, but will be 10 on early PC-1500s.

Consider this example:

<syntaxhighlight lang="basic">
10 S=0
20 FOR K=1 TO 10 STEP 4
30 S=S+1
40 NEXT K
50 PRINT S
</syntaxhighlight>

S will be set to 3 on later model PC-1500s and PC-1600s, but will be 4 on early PC-1500s.

Early model PC-1500s evaluate IF...THEN statements differently. The behaviour can be summarised thus:
{| class="wikitable"
|-
! Model
! {{yes|True}}
! {{no|False}}
|-
| PC-1600 / Later PC-1500
| ≠0
| 0
|-
| Early PC-1500
| >0
| <0
|}

An early model PC-1500 can be detected by using the command: <syntaxhighlight lang="basic" inline>PEEK&C5C0</syntaxhighlight>.

If the value returned is 6, it is an early model.