On 04.09.2014 15:52, David Barker wrote: [...] > I am writing on behalf of Argon Design, a small Cambridge-based design > consultancy. I am currently an intern there and have been spending the summer > looking into the feasibility of doing some future projects on the Raspberry > Pi. As part of this, I have been programming a demo app using the VideoCore > IV. In the course of developing this demo, I have discovered a few > differences from the current version of Herman's Programmers' Manual, and > would like to share them with the community: > > * rts (return from leaf function by copying lr -> pc): 0x005A That's an alias for b lr, I'm afraid. The vector stuff looks interesting, but largely beyond me --- I've never touched it. However: > * In the 32-bit scalar data section, there is the following: > 1100 00 op:5 d:5 a:5 c:4 10 u:5 <op><cc> rd, ra, #u > if (<cc>) rd = ra op u > From testing, it looks like it should really be > 1100 00 op:5 d:5 a:5 c:4 1 i:6 <op><cc> rd, ra, #i > if (<cc>) rd = ra op i ...I always thought that encoding was weird. Thanks! Incidentally, the big thing missing from the scalar instruction set is any form of adc or sbc instruction; this makes it really painful to do 64 bit arithmetic. If you happen to spot one, that would be awesome. -- ┌─── ｄｇ＠ｃｏｗｌａｒｋ．ｃｏｍ ───── http://www.cowlark.com ───── │ "Blue is beautiful... blue is best... │ I'm blue! I'm beautiful! I'm best!" │ --- _Dougal and the Blue Cat_
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