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From: Dave Brolley <brolley@redhat.com>
To: Mehak Mahajan <mehak.mahajan@gmail.com>
Cc: cgen@sources.redhat.com
Subject: Re: Is there a function in cgen for parsing short integers?
Date: Fri, 18 Apr 2008 15:24:00 -0000	[thread overview]
Message-ID: <4808BCFF.1060503@redhat.com> (raw)
In-Reply-To: <4807D8CD.20703@gmail.com>

You need to define your own parse handler for this operand. Take a look 
at the operand 'hi16' in cgen/cpu/openrisc.cpu and its parse handler 
'parse_hi16' in cgen/cpu/openrisc.opc. At the end, this particular 
handler chooses to extend the sign from bit 16. You could issue your 
error/warning at this point in the case of overflow.

I hope this helps,
Dave

Mehak Mahajan wrote:
> Hi,
>
> I am porting cgen to a 16 bit architecture. The immediates are 16 bits 
> long. I am also parsing all hex numbers as signed numbers. Hence 
> 0xFFFF will be -1.
> When I parse -1, I get 0xFFFFFFFF, since cgen_parse_signed_integer 
> accepts a long.
> My problem is that since the max size of immediate can only be 16 
> bits, I want to flag an error if the user enters an immediate like 
> 0xFFFFFFFF. However, since -1 is parsed as a long, there is no way for 
> me to restrict the length of the immediates to 16 bits.
>
> Is there an equivalent function for parsing short integers as well?
>
> Cheers,
> Mehak

  reply	other threads:[~2008-04-18 15:24 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-17 23:10 Mehak Mahajan
2008-04-18 15:24 ` Dave Brolley [this message]
2008-04-18 20:42 Mehak Mahajan
2008-04-19  0:09 ` Dave Brolley
2008-04-19 17:24   ` Dave Brolley

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