Power 6/32 - Revision history

Jnc: Comments on a few points

2024-12-27T00:38:45Z

Comments on a few points

Jnc: /* Opcode table */ Add number of operands for all instrs

2024-12-26T03:49:58Z

‎Opcode table: Add number of operands for all instrs

Show changes

Jnc: /* Instruction Set */ Explain 'indexed' addressing mode; note emulated instructions

2024-12-24T00:11:44Z

‎Instruction Set: Explain 'indexed' addressing mode; note emulated instructions

Jnc: /* External links */ +Installing and Operating 4.3BSD UNIX on the Tahoe

2024-12-23T01:35:37Z

‎External links: +Installing and Operating 4.3BSD UNIX on the Tahoe

Jnc: Fix links

2024-12-23T01:27:27Z

Fix links

Jnc: Add basic instruction layout, operand addressing modes

2024-12-22T19:48:02Z

Add basic instruction layout, operand addressing modes

Jnc: Used the VERSAbus as its bus

2024-12-21T15:23:29Z

Used the VERSAbus as its bus

Jnc: Convert URL to link; add some links

2024-12-20T12:12:30Z

Convert URL to link; add some links

Jonathanjo: /* External links */

2024-12-19T11:56:40Z

‎External links

Jonathanjo: Added instruction set

2024-12-19T11:22:04Z

Added instruction set

@@ Line 5: / Line 5: @@
 Although it was not very successful commercially (in part because CCI exited the computer business shortly after it was released), it was very influential as the first non-[[VAX]] machine that [[BSD]] [[UNIX]] was ported to. The Tahoe did help separate out a lot of VAX-specific code from the base, allowing BSD to become more portable, but the Power 6/32 machine quickly disappeared off the market, and not much is known about them.
-The [[Central Processing Unit|CPU]] was re-sold (under other names) in systems from several vendors (viewed by CCI as [[Original Equipment Manufacturer|OEMs]]): [[Unisys]] sold the 6/32 under the name 'Unisys 7000/40', using their own bastardized BSD+SYSV Unix. (Kuwait Petroleum in Denmark had one of them.) [[ICL]] had the 'Clan 7'. [[Harris]] had the HCX-5, -7, and -9 models (for which a small amount of information survives - below), running the [[UNIX System V|SysV]] derivative HCX/UX.
+The [[Central Processing Unit|CPU]] was re-sold (under other names) in systems from several vendors (viewed by CCI as [[Original Equipment Manufacturer|OEMs]]): [[Unisys]] sold the 6/32 under the name 'Unisys 7000/40', using their own bastardized BSD+SYSV Unix (Kuwait Petroleum in Denmark had one of them). [[ICL]] had the 'Clan 7'. [[Harris]] had the HCX-5, -7, and -9 models (for which a small amount of information survives - below), running the [[UNIX System V|SysV]] derivative HCX/UX.
 Pixar used a Power 6/32 to render the stained-glass knight in the 1985 movie ''Young Sherlock Holmes''.
@@ Line 76: / Line 76: @@
 :: The "indexed" mode apparently adds the contents of the named register to the [[address]] generated by the following operand. (It likely cannot be used with the "register immediate" addressing mode.)
-: For operands of the 6 'displacement' modes, the operand is followed by a value of the indicated length.
+:: Use of the 'auto-increment' addressing mode with the program counter as the register provides 'immediate' data.
 ===Opcode table===
@@ Line 154: / Line 156: @@
 |}
-A number of the more complex arithmetic instructions, many of them the [[floating point]] and the trigonometric ones (CVLF, CVLD, CVFL, CVDL, LDFD, CVDF, ADDF, ADDD, SUBF, SUBD, MULF, MULD, DIVF, DIVD, SINF, COSF, ATANF, LOGF, SQRTF and EXPF), do not seem to be implemented in the Power 6/32; instead, they were [[emulation|emulated]] in [[software]], after an attempt to execute them resulted in a [[trap]].
+There are a number of instructions which, according to the instruction list file, take 0 operands: ldpctx, pushd, etc, etc. If this is accurate, the only plausible explanation is that perhaps the actual operands are in defined register(s), or something like that.
 {{semi-stub}}

@@ Line 33: / Line 33: @@
 Although apparently no documentation survives and is accessible, we can infer a lot from the [[instruction]] decoding/printing routines in the [[debugger]]s from 4.3 BSD Tahoe, and their input file 'instrs' (below).
-* Instructions start with a 1-byte [[operation code|opcode]], and, depending on the opcode, are followed by 0-3 [[operand]]s. (Two instructions, 'ediv' and 'emul', take 4 operands.)
+* Instructions start with a 1-byte [[operation code|opcode]], and, depending on the opcode and 'addressing mode' (below), are followed by a basic set of 0-3 [[operand]]s. (Two instructions, 'ediv' and 'emul', take 4 operands; if any operand uses the 'indexed' addressing mode, an extra operand is required for each such use.)
 * Operands start with 1 byte, containing 4 bits of 'addressing mode' and 4 bits of '[[register]]':
 ** The CPU has sixteen 32-bit registers r0 ... r13 ([[stack frame|fp]]), r14 ([[Stack Pointer|sp]]), r15 ([[Program Counter|pc]]).
@@ Line 49: / Line 49: @@
 | 0x3 || short literals 48-63
 |-
-| 0x4 || indexed || i[r]
+| 0x4 || indexed || [r]
 |-
 | 0x5 || register immediate || r
@@ Line 74: / Line 74: @@
 |}
-:: (''It is not yet clear what the difference between "indexed" and "displacement" is.'')
+:: The "indexed" mode apparently adds the contents of the named register to the [[address]] generated by the following operand. (It likely cannot be used with the "register immediate" addressing mode.)
 : For operands of the 6 'displacement' modes, the operand is followed by a value of the indicated length.
@@ Line 133: / Line 133: @@
 | remque  || bcc/blssu || -       || -       || -       || -       || divf    || divd    || movblk  || pushab  || -       || pushaw  || casel   || pushal  || callf   || -
 |}
 {{semi-stub}}

@@ Line 145: / Line 145: @@
 * [https://virtuallyfun.com/wp-content/uploads/2017/02/Harris-HCX-9-print-ad.jpg Harris HCX-9] - ad
 * [https://virtuallyfun.com/2017/02/24/the-harris-hcx-9-aka-tahoe-platform/ The Harris HCX-9 aka TAHOE platform]
 * [https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD-Tahoe/usr/src/bin/adb adb] - debugger source
 * [https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD-Tahoe/usr/src/ucb/dbx/ dbx]

@@ Line 31: / Line 31: @@
 ==Instruction Set==
-Although apparently no documentation survives and is accessible, we can infer a lot from the [[instruction]] decoding/printing routines in the [[debug]]ers from [[4.3 BSD Tahoe]], and their input file 'instrs' (below).
+Although apparently no documentation survives and is accessible, we can infer a lot from the [[instruction]] decoding/printing routines in the [[debugger]]s from 4.3 BSD Tahoe, and their input file 'instrs' (below).
 * Instructions start with a 1-byte [[operation code|opcode]], and, depending on the opcode, are followed by 0-3 [[operand]]s. (Two instructions, 'ediv' and 'emul', take 4 operands.)

@@ Line 1: / Line 1: @@
 [[Image:Young-sherlock-holmes-knight.jpeg|thumb|right|3D rendering by a Power 6/32 in Young Sherlock Holmes]]
-The '''Power 6/32''', code named '''Tahoe''', from [[Computer Consoles Incorporated]], was the [[Central Processing Unit|CPU]] for a [[supermini]]; it used the [[VERSAbus]] as its [[bus]]. It is most noted from the [[Computer Systems Research Group|CSRG]] [[software port|porting]] [[4.3 BSD]] to it, in the [[4.3 BSD Tahoe]] release.
+The '''Power 6/32''', code named '''Tahoe''', from [[Computer Consoles Incorporated]], was a [[supermini]]; it used the [[VERSAbus]] as its [[bus]]. It is most noted from the [[Computer Systems Research Group|CSRG]] [[software port|porting]] [[4.3 BSD]] to it, in the [[4.3 BSD Tahoe]] release.
 Although it was not very successful commercially (in part because CCI exited the computer business shortly after it was released), it was very influential as the first non-[[VAX]] machine that [[BSD]] [[UNIX]] was ported to. The Tahoe did help separate out a lot of VAX-specific code from the base, allowing BSD to become more portable, but the Power 6/32 machine quickly disappeared off the market, and not much is known about them.
-It was re-sold (under other names) by several vendors: [[Unisys]] sold the 6/32 under the name 'Unisys 7000/40', using their own bastardized BSD+SYSV Unix. (Kuwait Petroleum in Denmark had one of them.) [[ICL]] had the 'Clan 7'. [[Harris]] had the HCX-5, -7, and -9 models (for which a bit survives - below), running the [[SysV]] derivative HCX/UX.
+The [[Central Processing Unit|CPU]] was re-sold (under other names) in systems from several vendors (viewed by CCI as [[Original Equipment Manufacturer|OEMs]]): [[Unisys]] sold the 6/32 under the name 'Unisys 7000/40', using their own bastardized BSD+SYSV Unix. (Kuwait Petroleum in Denmark had one of them.) [[ICL]] had the 'Clan 7'. [[Harris]] had the HCX-5, -7, and -9 models (for which a small amount of information survives - below), running the [[UNIX System V|SysV]] derivative HCX/UX.
 Pixar used a Power 6/32 to render the stained-glass knight in the 1985 movie ''Young Sherlock Holmes''.
@@ Line 11: / Line 11: @@
 ==Details==
-The Power 6/32 [[Central Processing Unit|CPU]] was implemented in [[transistor-transistor logic|TTL]]; it had a [[clock rate]] of 100nS.
+The Power 6/32 CPU was implemented in [[transistor-transistor logic|TTL]]; it had a [[clock rate]] of 100nS.
-All that I can find out about them is this table from dhrystone.c (below):
+The performance is given in this table, from dhrystone.c (below):
 <pre>
   *----------------DHRYSTONE VERSION 1.0 RESULTS BEGIN--------------------------
@@ Line 31: / Line 31: @@
 ==Instruction Set==
-We can infer a lot from the [[4.3 BSD Tahoe]] file 'instrs' (below):
+Although apparently no documentation survives and is accessible, we can infer a lot from the [[instruction]] decoding/printing routines in the [[debug]]ers from [[4.3 BSD Tahoe]], and their input file 'instrs' (below).
-* The CPU has sixteen 32-bit [[register]]s r0 ... r13 ([[stack frame|fp]]), r14 ([[Stack Pointer|sp]]), r15 ([[Program Counter|pc]]).
+* Instructions start with a 1-byte [[operation code|opcode]], and, depending on the opcode, are followed by 0-3 [[operand]]s. (Two instructions, 'ediv' and 'emul', take 4 operands.)
-* The opcode map and mnemonics for the [[assembly language|assembler]] are as follows:
+* Operands start with 1 byte, containing 4 bits of 'addressing mode' and 4 bits of '[[register]]':
 {| class="wikitable"
@@ Line 85: / Line 131: @@
 |-
 ! 0xf0
 | remque  || bcc/blssu || -       || -       || -       || -       || divf    || divd    || movblk  || pushab  || -       || pushaw  || casel   || pushal  || callf   || -
 |}
@@ Line 100: / Line 145: @@
 * [https://virtuallyfun.com/wp-content/uploads/2017/02/Harris-HCX-9-print-ad.jpg Harris HCX-9] - ad
 * [https://virtuallyfun.com/2017/02/24/the-harris-hcx-9-aka-tahoe-platform/ The Harris HCX-9 aka TAHOE platform]
-* [https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD-Tahoe/usr/src/bin/as/as.tahoe/instrs instrs] - basic table
+* [https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD-Tahoe/usr/src/bin/adb adb] - debugger source
 ** [https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD-Tahoe/usr/src/bin/adb/adb.tahoe/instrs instrs] - alphabetical list
 * [https://web.archive.org/web/20150123191735/http://www.dunnington.u-net.com/public/dhrystone.c dhrystone.c]

← Older revision		Revision as of 11:22, 19 December 2024
Line 29:		Line 29:

	Which may give some indication on the initial reasons why the Power 6/32 was chosen as the successor to the VAX by CSRG.		Which may give some indication on the initial reasons why the Power 6/32 was chosen as the successor to the VAX by CSRG.
		+
		+	==Instruction Set==
		+
		+	We can infer a lot from the 4.3BSD-tahoe source file <code>usr/src/bin/as/as.tahoe/instrs</code>
		+
		+	* The CPU has sixteen 32-bit registers r0 ... r13 (fp), r14 (sp), r15 (pc).
		+	* The opcode map and mnemonics for the assembler are as follows:
		+
		+	{\| class="wikitable"
		+	! \|\| 0 \|\| 1 \|\| 2 \|\| 3 \|\| 4 \|\| 5 \|\| 6 \|\| 7 \|\| 8 \|\| 9 \|\| a \|\| b \|\| c \|\| d \|\| e \|\|f
		+	\|-
		+	! 0x00
		+	\| halt \|\| - \|\| - \|\| - \|\| - \|\| sinf \|\| ldf \|\| ldd \|\| addb2 \|\| movb \|\| addw2 \|\| movw \|\| addl2 \|\| movl \|\| bbs \|\| -
		+	\|-
		+	! 0x10
		+	\| nop \|\| brb \|\| - \|\| brw \|\| - \|\| cosf \|\| lnf \|\| lnd \|\| addb3 \|\| cmpb \|\| addw3 \|\| cmpw \|\| addl3 \|\| cmpl \|\| bbc \|\| -
		+	\|-
		+	! 0x20
		+	\| rei \|\| bneq/bnequ \|\| - \|\| cvtwl \|\| - \|\| atanf \|\| stf \|\| std \|\| subb2 \|\| mcomb \|\| subw2 \|\| mcomw \|\| subl2 \|\| mcoml \|\| emul \|\| aoblss
		+	\|-
		+	! 0x30
		+	\| bpt \|\| beql/beqlu \|\| - \|\| cvtwb \|\| - \|\| logf \|\| cmpf \|\| cmpd \|\| subb3 \|\| bitb \|\| subw3 \|\| bitw \|\| subl3 \|\| bitl \|\| ediv \|\| aobleq
		+	\|-
		+	! 0x40
		+	\| ret \|\| bgtr \|\| - \|\| - \|\| - \|\| sqrtf \|\| cmpf2 \|\| cmpd2 \|\| shll \|\| clrb \|\| shlq \|\| clrw \|\| mull2 \|\| clrl \|\| shal \|\| -
		+	\|-
		+	! 0x50
		+	\| - \|\| bleq \|\| - \|\| - \|\| - \|\| expf \|\| tstf \|\| tstd \|\| shrl \|\| tstb \|\| shrq \|\| tstw \|\| mull3 \|\| tstl \|\| shar \|\| bbssi
		+	\|-
		+	! 0x60
		+	\| ldpctx \|\| - \|\| - \|\| - \|\| - \|\| - \|\| - \|\| pushd \|\| - \|\| incb \|\| - \|\| incw \|\| divl2 \|\| incl \|\| - \|\| cvtlb
		+	\|-
		+	! 0x70
		+	\| svpctx \|\| jmp \|\| - \|\| - \|\| - \|\| - \|\| cvlf \|\| cvld \|\| - \|\| decb \|\| - \|\| decw \|\| divl3 \|\| decl \|\| - \|\| cvtlw
		+	\|-
		+	! 0x80
		+	\| - \|\| bgeq \|\| movs2 \|\| - \|\| - \|\| - \|\| cvfl \|\| cvdl \|\| orb2 \|\| cvtbl \|\| orw2 \|\| bispsw \|\| orl2 \|\| adwc \|\| adda \|\| -
		+	\|-
		+	! 0x90
		+	\| - \|\| blss \|\| cmps2 \|\| - \|\| - \|\| - \|\| - \|\| ldfd \|\| orb3 \|\| cvtbw \|\| orw3 \|\| bicpsw \|\| orl3 \|\| sbwc \|\| suba \|\| -
		+	\|-
		+	! 0xa0
		+	\| - \|\| bgtru \|\| - \|\| - \|\| - \|\| - \|\| cvdf \|\| - \|\| andb2 \|\| movzbl \|\| andw2 \|\| loadr \|\| andl2 \|\| mtpr \|\| ffs \|\| -
		+	\|-
		+	! 0xb0
		+	\| - \|\| blequ \|\| - \|\| - \|\| - \|\| - \|\| negf \|\| negd \|\| andb3 \|\| movzbw \|\| andw3 \|\| storer \|\| andl3 \|\| mfpr \|\| ffc \|\| calls
		+	\|-
		+	! 0xc0
		+	\| prober \|\| bvc \|\| movs3 \|\| movzwl \|\| - \|\| - \|\| addf \|\| addd \|\| xorb2 \|\| movob \|\| xorw2 \|\| movow \|\| xorl2 \|\| movpsl \|\| btcs \|\| kcall
		+	\|-
		+	! 0xd0
		+	\| probew \|\| bvs \|\| cmps3 \|\| - \|\| - \|\| - \|\| subf \|\| subd \|\| xorb3 \|\| pushb \|\| xorw3 \|\| pushw \|\| xorl3 \|\| pushl \|\| - \|\| -
		+	\|-
		+	! 0xe0
		+	\| insque \|\| bgequ/bcs \|\| - \|\| - \|\| - \|\| - \|\| mulf \|\| muld \|\| mnegb \|\| movab \|\| mnegw \|\| movaw \|\| mnegl \|\| moval \|\| - \|\| -
		+	\|-
		+	! 0xf0
		+	\| remque \|\| bcc/blssu \|\| - \|\| - \|\| - \|\| - \|\| divf \|\| divd \|\| movblk \|\| pushab \|\| - \|\| pushaw \|\| casel \|\| pushal \|\| callf \|\| -
		+
		+	\|}

	{{semi-stub}}		{{semi-stub}}