Retro/pcjs
Watch
1
0
Fork
You've already forked pcjs
 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Laid groundwork for MMU-specific functions, to avoid address mapping work when unnecessary

Browse source
This commit is contained in:
Jeff 2016-09-25 12:12:26 -07:00 • committed by Jeff Parsons
commit da617d454d
6 changed files with 804 additions and 687 deletions
Download patch file Download diff file Expand all files Collapse all files

31
modules/pdp11/lib/defines.js
View file

@ -226,7 +226,8 @@ var PDP11 = {
BYTE: 0x1,
READ: 0x2,
WRITE: 0x4,
UPDATE: 0x6
UPDATE: 0x6,
DSPACE: 0x10000 // set bit 17 in any 16-bit virtual address that refers to D space (as opposed to I space)
},
/*
* Internal flags passed to writeByteByMode(), etc.
@ -276,13 +277,17 @@ var PDP11 = {
/*
* Assorted special (UNIBUS) addresses
*
* Within the PDP-11's 18-bit address space, of the 0x40000 possible addresses, the top 8Kb (0x2000)
* is called the IOPAGE and is reserved for CPU and I/O registers. The IOPAGE spans 0x3E000-0x3FFFF.
* Within the PDP-11/45's 18-bit address space, of the 0x40000 possible addresses (256Kb), the top 0x2000
* (8Kb) is called the IOPAGE and is reserved for CPU and I/O registers. The IOPAGE spans 0x3E000-0x3FFFF.
*
* To map UNIBUS addresses to 22-bit physical addresses, a UNIBUS relocation map is used. It consists
* of 31 double-word registers that each hold a 22-bit base address. When UNIBUS relocation is enabled,
* the top 5 bits of an address select one of the 31 mapping registers, and the bottom 13 bits are then
* added to the contents of the selected mapping register.
* Within the PDP-11/70's 22-bit address space, of the 0x400000 possible addresses (4Mb), the top 0x20000
* (256Kb) is mapped to the UNIBUS (not physical memory), and as before, the top 0x2000 (8Kb) of that is
* mapped to the IOPAGE.
*
* To map 18-bit UNIBUS addresses to 22-bit physical addresses, the 11/70 uses a UNIBUS relocation map.
* It consists of 31 double-word registers that each hold a 22-bit base address. When UNIBUS relocation
* is enabled, the top 5 bits of an address select one of the 31 mapping registers, and the bottom 13 bits
* are then added to the contents of the selected mapping register.
*
* ES6 ALERT: By using octal constants, this is the first place I'm dipping my toe into ECMAScript 6 waters.
* If you're loading this raw source code into your browser, then by now (2016) you're almost certainly using
@ -293,11 +298,15 @@ var PDP11 = {
* For more details: https://github.com/google/closure-compiler/wiki/ECMAScript6
*/
UNIBUS: { //16-bit 18-bit 22-bit Hex Description
PSW: 0o177776, // 777776 17777776 0x3FFFFE PSW
SL: 0o177774, // Stack Limit
PSW: 0o177776, // 777776 17777776 0x3FFFFE Processor Status Word
SL: 0o177774, // Stack Limit Register
PIR: 0o177772, // Program Interrupt Request
MB: 0o177770, // Microprogram break
CPUERR: 0o177766, // CPU error
MB: 0o177770, // Microprogram break (11/70 only?)
CPUERR: 0o177766, // CPU error (11/70 only?)
SYSID: 0o177764, // System ID Register (11/70 only?)
SIZE_HI: 0o177762, // Upper Size Register (always zero) (11/70 only?)
SIZE_LO: 0o177760, // Lower Size Register (last 32-word block) (11/70 only?)
DISPLAY: 0o177570, // Console Switch and Display
MMR0: 0o177572, // 777572 17777572
MMR1: 0o177574, // 777574 17777574
MMR2: 0o177576, // 777576 17777576