Hi, my Z-80 emulator is coming along very nicely actually I'm making progress on it much faster than I had expected, but I've run into a road block. There are some unofficial instructions in the Z-80 instruction with the "CBh" prefix instructions CB30h~CB37h are not official by Zilog but perform some function. Their mnemonics are "SLL" Does anyone know anything about these instructions? There are some Z-80 programmers out there that probably used it but I've never used unofficial instructions.






CB30 SLL B*
CB31 SLL C*
CB32 SLL D*
CB33 SLL E*
CB34 SLL H*
CB35 SLL L*
CB36 SLL (HL)*
CB37 SLL A*

Posted on 2003-06-26 22:21:05 by x86asm
Posted on 2003-06-27 01:16:40 by arkane
Hi x86asm,

All CB-shifted opcodes are defined, except the range CB 30 to CB 37. This first group of undocumented codes are usually referred to as "Shift Left Logical". The byte referenced is shifted one bit to the left just like the documented SLA instruction. Unlike that instruction however, SLL causes the Least Significant Bit to be set to a "1".


From : http://www.greew.freeserve.co.uk/Z80Undoc.html


or MSX offical forum about your question:

http://www.msx.org/forumtopicl912.html


Regards,
Posted on 2003-06-27 14:29:02 by CYDONIA