[Tuxnes-devel] yet more asm stuff--carry f

[Rigel <ri...@an...>]

My apologies for my inferior mail service--it appears I've not been receiving all my mail.  (And they're using Linux servers here, too!)  So I had to look this up in the archive...
At 10:28am on 2001 April 12, Rigel did write:

>> heads up here.  I don't understand the implementation in table.x86.  So
>> on all these listed instructions I set carry flag if there was a carrry
>> (and clear it otherwise)?

>Yes.  What trouble are you having with the implementation?
>When carry is set, ebp is -1.  When carry is clear, ebp is 0.
>For instructions which may carry, the sequence is:

>addl -1, %ebp                 # set i386 carry if %ebp >was set
><instruction which may carry> # set i386 carry according to 6502 instruction
>sbbl %ebp, %ebp               # set %ebp to -1 on >carry, else clear

>Like I said, check out SEC, CLC and ROR -
>Accumulator, these are the
>simplest examples.

Okay, I get that much.  However, Mips doesn't necessarily have a flags reg (I don't think).  so would this be right?
let's say the operation is sh left, so in C:

modified=orig<<1;
carryf = modified ^ orig; // ^ is xor operator (?)

I believe this to be accurate if we're doing binary math, but yell at me if I'm wrong.

And an aside to Mike.  I do have root privileges on the previously mentioned SGI.  Now I want to put gcc on it.  How?  I've been to sgi.com/developers/devtools/apis/...html (their idf and idl stuff) but when I try to install it, the inst program gives me a failed dependency error.  Any clues, or do you even run irix?


Who needs Cupid?  Matchmaker.com is the place to meet somebody.
FREE Two-week Trial Membership at http://www.matchmaker.com/home?rs=200015