Difference between revisions of "PDP-11 Second Processor"
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| − | [[Category:Second_Processors]] | + | [[Category:Second_Processors]]__NOTOC__ |
| − | __NOTOC__ | ||
An emulated [[Second Processor]] for the BBC/Master containing a DEC PDP-11. | An emulated [[Second Processor]] for the BBC/Master containing a DEC PDP-11. | ||
| Line 90: | Line 89: | ||
R0=0 - Loads and enters BASIC | R0=0 - Loads and enters BASIC | ||
R1=0 or R1=>parameters | R1=0 or R1=>parameters | ||
| − | R0=1 - | + | R0=1 - Set up new program environment - default environment handlers only. |
| − | R0=2 - | + | R0=2 - Set up software environment - default environment handlers and EMTs. |
| + | R0=3 - Set up hardware environment - default environment handlers, EMTs, | ||
| + | hardware vectors | ||
On exit: | On exit: | ||
All preserved | All preserved | ||
| Line 105: | Line 106: | ||
If R0<0, the call sets and reads the following environment handlers: | If R0<0, the call sets and reads the following environment handlers: | ||
| − | R0 R1 | + | R0 R1 R2 |
| − | -1 Exit handler | + | -1 Exit handler Version |
| − | -2 Escape handler | + | -2 Escape handler Escape flag |
| − | -3 Error handler | + | -3 Error handler Error buffer |
| − | -4 Event handler | + | -4 Event handler ignored |
| − | -5 Unknown IRQ handler | + | -5 Unknown IRQ handler ignored |
| − | -6 ignored | + | -6 ignored EMT dispatch table |
| + | Internal handlers | ||
| + | -7 SPARE LPTR | ||
| + | -8 MEMBOT MEMTOP | ||
| + | -9 ADDRlo ADDRhi | ||
| + | -10 PROG ESCFLG | ||
</pre> | </pre> | ||
=== EMT &0F - OS_ERROR === | === EMT &0F - OS_ERROR === | ||
| Line 122: | Line 128: | ||
== See also == | == See also == | ||
| − | * [[BBC BASIC | + | * [[PDP11 BBC BASIC]] |
[[User:Jgharston|Jgharston]] 18:31, 11 September 2008 (BST) | [[User:Jgharston|Jgharston]] 18:31, 11 September 2008 (BST) | ||
| + | [[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 00:07, 31 January 2016 (UTC) | ||
Revision as of 02:07, 31 January 2016
An emulated Second Processor for the BBC/Master containing a DEC PDP-11.
The PDP-11 client MOS provides the basic system required to communicate with the host computer as well as a cut-down set of PDP-11 Unix functions.
Software and documentation for the PDP-11 CoProcessor are available at mdfs.net.
MOS API Calls
Programs communicate with the kernal and MOS via the EMT trap instruction. Parameters are passed in registers R0 onwards.
On entry, R0-R7 contain values to pass to EMT call
On exit, R0-R7 contain returned data
V=0 - no error occured
V=1 - error occured, R0=>error block
EMT &00 - OS_QUIT
On entry: On exit: R0=Return value
EMT &01 - OS_CLI
On entry: On exit: R0=>command string R0=Return value
EMT &02 - OS_BYTE
On entry: On exit
R0=function R0=preserved
R1=first parameter R1=returned word
R2=second parameter R2=returned word DIV 256
Cy=returned carry flag
EMT &03 - OS_WORD
On entry: On exit: R0=function Control block updated R1=>control block R1=returned line length for OSWORD 0
EMT &04 - OS_WRCH
On entry: On exit: R0=character R0=preserved
EMT &05 - OS_NEWL
On entry: On exit:
R1=13
EMT &06 - OS_RDCH
On entry: On exit:
R0=character
Cy=carry flag
EMT &07 - OS_FILE
On entry: On exit: R0=function R0=result R1=>control block R1=preserved
EMT &08 - OS_ARGS
On entry: On exit: R0=function R0=result R1=handle R1=preserved R2=>data R2=data
EMT &09 - OS_BGET
On entry: On exit:
R0=byte
R1=handle R1=preserved
Cy=carry flag
EMT &0A - OS_BPUT
On entry: On exit: R0=byte R0=preserved R1=handle R1=preserved
EMT &0B - OS_GBPB
On entry: On exit:
R0=function
R1=>control block R1=preserved
Cy=carry flag
EMT &0C - OS_FIND
On entry: On exit: R0=function R0=handle R1=>string or handle
EMT &0D - OS_SYST
On entry:
R0=0 - Loads and enters BASIC
R1=0 or R1=>parameters
R0=1 - Set up new program environment - default environment handlers only.
R0=2 - Set up software environment - default environment handlers and EMTs.
R0=3 - Set up hardware environment - default environment handlers, EMTs,
hardware vectors
On exit:
All preserved
EMT &0E - OS_HANDLER
On entry: On exit: R0=EMT or handler number R0=preserved R1=handler or 0 to read R1=previous handler R2=buffer or 0 to read R2=previous buffer If R0>=0, the call redirects the specified EMT call, returning the previous handler If R0<0, the call sets and reads the following environment handlers: R0 R1 R2 -1 Exit handler Version -2 Escape handler Escape flag -3 Error handler Error buffer -4 Event handler ignored -5 Unknown IRQ handler ignored -6 ignored EMT dispatch table Internal handlers -7 SPARE LPTR -8 MEMBOT MEMTOP -9 ADDRlo ADDRhi -10 PROG ESCFLG
EMT &0F - OS_ERROR
EMT &0F is followed by the error block in memory: EMT 15 EQUB error EQUS "error string" EQUB 0
See also
Jgharston 18:31, 11 September 2008 (BST) Jgharston (talk) 00:07, 31 January 2016 (UTC)
