From 24170e07cc841eb8ed93df5bc298d42f3351addb Mon Sep 17 00:00:00 2001 From: Ivan Date: Mon, 22 Aug 2016 13:17:15 +0300 Subject: [PATCH] OE bit info removed --- Developer-Information.md | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/Developer-Information.md b/Developer-Information.md index 305572d..12e1bd9 100644 --- a/Developer-Information.md +++ b/Developer-Information.md @@ -29,16 +29,6 @@ Best wishes and happy coding! ## Information -####OE bit -Some instructions contain an optional `OE`(overflow excpetion) flag. We currently do not implement those versions of the instructions. For example we emulate `add`, `addze`, `subfme` but not `addo`, `addzeo`, `subfmo` which are just the prior operations with the `OE` flag set. - -This flag writes to the `OV` and `SO` (overflow and summary overflow) bits of the XER (Fixed-Point Exception Register) register. The reason why it's not implemented is that the [GCC code emitter](http://repo.or.cz/w/official-gcc.git/blob_plain/c2c80e70905bc2e5dedf8352588fc8cb10e3ec7d:/gcc/config/rs6000/rs6000.md) does not use these instructions and so we haven't found any PS3 software that uses it. - -If we find some software that has some handwritten assembly that use those instructions we'll need to implement it (or just for completeness). A good reference for XER bits can be found in [PowerPC Microprocessor Family: The Programmer's Reference Guide ](https://www-01.ibm.com/chips/techlib/techlib.nsf/techdocs/852569B20050FF778525699600741775) chapter 1.3 and other linked references. - -Probably something from the [answers to this SO question](http://stackoverflow.com/questions/199333/best-way-to-detect-integer-overflow-in-c-c) is what we could consider. - - ####Misc (Some of this information can be deleted, or at least it should be properly organized). * `sizeof(char)` = 1 (= 8 bits)