Nicron #07 14 ноября 1996

Железо

Iron - an overview of the microprocessor Zilog Z380, continued.

                          MPU Z380

(C) WLODEK BLACK


           Microprocessor Z380. Continued.

           Beginning in room 6.

Hello again, friends! Nice to know that your work
benefits. Already received the first response - enthusiastic,
I must say! And indeed, this chip that is worthy. Zaglyanemka 
that he was inside? .. Yeah, everything seems to be familiar: 
the battery, and flags, HL, DE, BC, the index registers IX and 
IY, the pointer stack, program counter, register regeneration 
RAM R, register interrupt vectors I. .. Here is a map register 
space, which I reproduce symbols pseudographics, defiantly 
expanding its three-dimensionality to the left (in the original 
- right): 



                                        A F


                    BCz B C


                    DEz D E


                    HLz H L


                    IXz IXU IYU


                    IYz IYU IYL



                                        A 'F'


                    BCz 'B' C '


                    DEz 'D' E '


                    HLz 'H' L '


                    IXz 'IXU' IYU '


                    IYz 'IYU' IYL '



                                        R


                     Iz I



                    SPz SP


                    PCz PC


As you can see, a set of general-purpose registers (GPR) looks 
pretty familiar. The difference with the Z80 is that in each of 
two sets - the mainstream and alternative - a quadruple set 
similar to appoint Ron, and enhanced registers to 32 bits. RON 
is used for storing and processing data and for addressing 
memory, and restrictions on the ways of addressing a 380-th 
significantly less. Treatment of RON defined in the codes of 
commands plus the active register slot is given by bits of the 
control register SR. Note: halves, index registers appeared 
official mnemonics - IXU, IYU for older halves and IXL, IYL for 
the youngest. (Offer in the manner of delusion: it can take 
into account appeared in the new standard and assembler for 
Z80, support mnemonics like "LD LX, E"?). Not hard to guess 
that suffix "z" denotes the union of the register line in 
32-bit register, but only in the descriptions, but not in 
mnemonic operations. 


                    Control register SR.


<------------ YSR ------------> <------------- XSR -------- ->


  0 0 0 0 0 IY bank IYP 0 0 0 0 0 IX bank IXP


  31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16



<--------- DSR -------------->

                     Main IEF
 0 0 0 0 0 Bank Alt XM LW 1 IM 0 LCK AFP

 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

IYBANK - 2-bit field select bank IY-registers. Contains a 
number (0 ... 3) the bank or IY IY '. After RESET is reset to 
0. 

IYP - bit of a choice of primary or alternate block registers
IY. 0 - the core set, 1 - an alternative set.

IXBANK, IXP - the same for the IX.

MAINBANK - 2-bit field selection unit registers AF, HL, DE, BC 
and A ', F', HL ', DE', BC '. Contains the number of register 
bank. 

ALT - bit of a choice of primary or alternative set of HL, DE, 
BC. 0 - primary, 1 - alternative.


XM (Extended Mode) - bits set the operation mode of the 
processor. 1 - Advanced mode 0 - mode Z80. Switch back to 0

not (only RESET; even POP does not help).

LW (Long Word mode) - bit control mode ", the word" / "long 
term". 1 - a long word, 0 - normal (16-bit) word. (For single 
instruction can be set individually mode word length, operating 
only within one team, with special teams). RESET resets to 0.


IEF1 - flag permits maskable interrupts. 1 - Interrupt
allowed, 0 - interrupt disabled. RESET resets to 0.

IM - 2-bit field mode interrupt 0,1,2 or 3.

LCK (Lock) - lock-bit service requests to access
the system bus by other devices. 1 - external requests
ignored, 0 - external requests are serviced. RESET resets to 0.

AFP - bit of a choice of primary or alternate block registers
AF (AF or AF '). 0 - primary, 1 - alternative.

Register SR software is available as a 32-bit SR, such as 3 
eight-bit register YSR, XSR and DSR, and can also be saved 
through PUSH and downloaded via POP. 

(To be continued).