On Fri, 27 Oct 2000 21:45:11 -0700, you wrote:

>Hi Everyone.
>
>I've encountered an interesting problem porting a small application
>from a 16C77 to an 18C452. I'm using HI-TECH PIC C on the '77 and
>HI-TECH PIC18 C on the '452.
>
>The problem involves reading the 16-bit register Timer1. On the '77,
>TMR1H and TMR1L are both readable, and so I declare:
>
>        static volatile unsigned INT TMR1 @ 0x0E;
>
>and do something like
>
>        counter =3D -TMR1;
>
>and that works fine. The trouble is that on the '452, TMR1H is only
>updated (it's really just a holding register) when TMR1L is read, and
>unluckily for me
>
>        counter =3D -TMR1;
>
>compiles/assembles to code that reads the high byte first, then the
>low byte, and so the result in <counter> is worthless.
>
>What is an elegant way to stay as much as possible in 16-bit land yet
>"persuade" the compiler to read the low byte first?
I wouldn't bother. If you need a specific order it is far better to do
it explicitly, otherwise you may get bitten if the compiler changes.=20
 counter =3D TMR1L=20
 counter |=3D TMR1H<<8
should be no less code-efficient and it is more 'obvious' what is
required.

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