Thread View: comp.sys.tahoe
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2 total messages
Started by John G Dobnick
Thu, 24 Jan 1991 19:39
What is the BTCS instruction ?
Author: John G Dobnick
Date: Thu, 24 Jan 1991 19:39
Date: Thu, 24 Jan 1991 19:39
26 lines
1543 bytes
1543 bytes
We received some code to fix a problem on our tahoe machine -- code which uses the BTCS instruction. While the assembler seems to know what this is, it is _not_ described in any of the manuals we have available. This makes it slightly difficult to understand just what the code is doing. (I believe we have the most current manuals our vendor supplies. This does not mean they are _really_ current, however.) My Question of the Day is: What is this BTCS instruction? Ideally, I seek a response that provides all the information that the architecture reference manual supplies for the other instructions -- to wit, instruction format, operand specifications, description of operation, "pseudo code" description of the instruction, condition codes, etc. Thank you for whatever information you can supply, -- John G Dobnick (JGD2) Computing Services Division @ University of Wisconsin - Milwaukee INTERNET: jgd@csd4.csd.uwm.edu ATTnet: (414) 229-5727 UUCP: uunet!uwm!csd4.csd.uwm.edu!jgd "Knowing how things work is the basis for appreciation, and is thus a source of civilized delight." -- William Safire
Re: What is the BTCS instruction ?
Author: Mark Smith
Date: Tue, 29 Jan 1991 18:11
Date: Tue, 29 Jan 1991 18:11
64 lines
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In article <9101241939.AA19540@csd4.csd.uwm.edu> jgd@CSD4.CSD.UWM.EDU (John G Dobnick) writes: >We received some code to fix a problem on our tahoe machine -- code >which uses the BTCS instruction. While the assembler seems to know >what this is, it is _not_ described in any of the manuals we have >available. This makes it slightly difficult to understand just what >the code is doing. (I believe we have the most current manuals our >vendor supplies. This does not mean they are _really_ current, however.) > >My Question of the Day is: > > What is this BTCS instruction? > >Ideally, I seek a response that provides all the information that the >architecture reference manual supplies for the other instructions -- >to wit, instruction format, operand specifications, description of >operation, "pseudo code" description of the instruction, condition >codes, etc. > Chapter 8 (Instruction Set) of the Harris Computer Systems Division HCX-7 and HCX-9 Architecture Manual (Publication Number 0830022-100) decribes the BTCS instruction as follows: BTCS BRANCH TO CONTROL STORE Purpose: Custom design of new instructions Format: opcode operand Condition Code Settings: N Z V C Exceptions: None Related Opcodes: 0xCE - Branch to WCS Detailed Description: Branch to one of sixteen WCS locations. This instruction allows the addition of customized instructions for specialized functions. Processing Details: Branch to one of sixteen unique WCS locations pointed to by the last four bits of htet operand. btcs() /*********************************************/ /*BRANCH TO ONE OF SIXTEEN WCS LOCATIONS */ /*********************************************/ ------------------------------------------------------------------------ That's it. Hope it helps. >Thank you for whatever information you can supply, >-- >John G Dobnick (JGD2) >Computing Services Division @ University of Wisconsin - Milwaukee >INTERNET: jgd@csd4.csd.uwm.edu ATTnet: (414) 229-5727 >UUCP: uunet!uwm!csd4.csd.uwm.edu!jgd > >"Knowing how things work is the basis for appreciation, >and is thus a source of civilized delight." -- William Safire Mark Smith Internet: mark@flipper.csd.harris.com UUCP: ...!uunet!travis!flipper!mark Mark Smith Internet: mark@flipper.csd.harris.com UUCP: ...!uunet!travis!flipper!mark
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