I2040401@DBSTU1.BITNET (04/07/89)
The new Zilog Z280 processor is not a rumour! It is available in
Germany for 59.61 DM (some 32 US$, without VAT, single unit
price). The lastest revision is "J". It has no longer the cache
problem that was known with revision "G".
Some features have been mentioned on the net but there are still
more highlights:
- It is fully software compatible with the Z80.
- It uses less memory cycles than the Z80, e.g.
EX DE,HL EXX LD A,B all use only 2 cycles
- It has new addressing modes:
It has 16 bit displacements, e.g. LD A,(IX+1234H)
It has a PC-relative addressing mode.
It has a SP-relative addressing mode, e.g. LD (SP+1234H),5
It has a so called "base index" addressing mode, e.g.
LD (HL+IX),6 LD (HL+IY),7 LD (IX+IY),8
You can also use 16 bit displacements with HL: LD A,(HL+5678H)
- Some other highlights:
You can use the lower and upper half of the IX and IY registers
individually (just as with HL). They are called IXL,
IXH, IYL and IYH, e.g. "LD A,IXH". (These were unofficial
instructions with the Z80.)
It has 16 bit arithmetic, e.g.
ADDW HL,1234H 16 bit add
CPW HL,BC 16 bit compare
DECW (1234H) 16 bit decrement
DIVW DEHL,1234H 16 bit divide
DIVUW DEHL,BC 16 bit unsigned divide
also signed and unsigned 16 bit multiply
(there are also multiply and divide for 8 bits)
NEG HL 16 bit twos complement
SUBW HL,DE no longer OR A SBC HL,DE
You can do
CALL (HL)
CALL cc,(HL) conditional call
INW HL,(C) 16 bit I/O
PUSH 1234H
LD (1234H),5678H
and several other instructions, e.g. to handle the on-chip
peripherals.
As far as I know the Z280 is the same chip as the one announced as
Z800 some years ago. It is not the same as the Z180 (= Hitachi 64180)
which has only a few new instructions.
Ulf Gruene
Technische Universitaet Braunschweig
West Germany
I2040401@DBSTU1.BITNETfifi@cosmo.UUCP (A.F.Zinser) (04/09/89)
In article <> I2040401@DBSTU1.BITNET (Ulf Gruene) writes: > - It is fully software compatible with the Z80. That's right, if you only use the official Z80-instruction-set, but who does. If you use the SLIA (shift left inverted arithmetic) as I do, you get into a conflict, because this instruction- sequence means TSET (Z280). And this difference is even mentioned by Zilog in it's own Z280 Technical Manual (see Appendix A)! > >Z800 some years ago. It is not the same as the Z180 (= HD64180) >which has only a few new instructions. Unfortunately the instruction-sets of Z180 and Z280 are so much different, that you can't use a Z180-assembler to create Z280- opcode... Does anybody on the net know about a Z280-assembler (or a pre-assembler to use an existing Z80-assembler)? +-------------------------------------------------------------------------+ | _ _ ! ! Axel F. Zinser (_!_) (_!_) ...uunet!mcvax!unido!cosmo!fifi | | Hannover, BRD ! ! fifi@cosmo.UUCP ! ! ! +-------------------------------------------------------------------------+