TUHS April 2022

tuhs@tuhs.org

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Re: [TUHS] Why does shell write to stderr?

by Douglas McIlroy

How would you wish to interact with /bin/bash >file Doug

2 years, 8 months

Re: [TUHS] Interesting commentary on Unix from Multicians.

by jnc＠mercury.lcs.mit.edu

> From: Clem Cole > Not to put too fine a point on it, It seems like it would be fair to > say Multics was 'complete' by the time Organick published his book This is a pretty ill-judged claim, IMO - but not for any particulars about the Organick book, etc. The problem is more global. When was UNIX 'complete' - when the first people were able to do real work on the PDP-7? When non-programmer clerks from the patent group were able to use the assembler UNIX on the PDP-11 to format parent documents? When it was re-written in C for the 4th Edition (since the _portability_ of UNIX was IMO perhaps the greatest factor in its eventual domination)? Etc, etc, etc. The exact same problem applies to the question of 'when was Multics 'complete''. > don't know when it first appeared and can not seem to find it. ... I > bet I have the 3rd printing. ... Anyone have a first edition around > with the publication date? The third printing _is_ the first edition. Anyway, it doesn't matter - see above. And of course even if the book _wriring_ was finished at time T, it wouldn't have been printed until some unknown time later. So that's really pretty useless as a temporal marker; we have much better ones availablw. > From: Dan Cross > I can't see any indication that this is anything other than the first > printing. My 3rd printing says 3rd was 1980, 2nd in 1976, and copyright 1972. > Organick's book is often said to describe an earlier version of the > system Yes; I'm not sure if the version described in it was ever available for general usege (which could be my definition of 'complete') - or even usage my Multics system programmers. I don't remember all the details of the differences (it's been way too long since I read it, and I don't know the details of the 'first operational' Multics well enough), but for instance: ISTR that it describes a version which had a linkage segment (holding intermediate locations in outbound links - since segment >a>b>c might well have different segment numbers assigned to it in the address spaces of processes X and Y, so one copy of >a>b>c, shared between X and Y, couldn't contain direct outbound links) _per segment_ (data or code) - but operational Multics (I don't know if this is from 'first available to users', or 'first available to Multics system programmers', or what) collapsed all the linkage info into a 'combined linkage segment', in which the linkage info from all the segments in a process' address space were combined (by copying) into a single linkage segment. Etc, etc, etc. > I understand that Multics got much better after the move to the 6180 I'm not sure that the 6180 made that big a difference to the environment the average use saw. My understanding (not having been there) was that the big _architectural_ difference was that cross-ring inter-segment references were done and monitored in hardware, so a host of security holes caused by insufficient checking of cross-ring inter-segment pointers were caught automatically. (The 6180 was also built out of SSI chips, unlike the 645 which was individual transistors, like a KA10.) Noel

2 years, 8 months

Re: [TUHS] Why does shell write to stderr?

by Paul Ruizendaal

> If you never ring the bell in the editor, the issue never comes up As natural language ambiguity was brought up: it makes the code less noisy :^)

2 years, 8 months

Why does shell write to stderr?

by Richard Salz

Looking at https://unix.stackexchange.com/questions/380012/why-does-bash-interactive-s…, in particular the first answer which has a link to http://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/sh/main%E2%80%8… Made me wonder: why?

2 years, 8 months

Long term software archive

by Jon Steinhart

So this is weird. My publisher contacted me this week asking for permission to send a copy of my book to these folks: https://archiveprogram.github.com/ Hadn't heard of them before. Looks like they're filling their archive with stuff from github which means that most of the stuff being preserved by TUHS is likely not there. Might be a good idea to see if it can be included. I have no contact with these folks but can probably get a contact from my publisher if this is something that y'all think is worth doing. Jon

2 years, 8 months

Re: [TUHS] A Reiser tour do force

by Paul Ruizendaal

> A not-very-thorough search at tuhs turned up V9/jerq/src/lib/j/bitblt.c > It appears to be a pre-Reiser bitblt, not what was asked for. The Reiser code is in the V8 jerq tarball that Dan Cross donated: v8jerq.tar.bz2 <https://www.tuhs.org/Archive/Distributions/Research/Dan_Cross_v8/v8jerq.tar…> It is in file blit/src/libj/bitblt.s (attached below for convenience). It is 750 lines of 68K assembler. It does not appear to have been ported to the Bellmac 32 CPU. Maybe it did not make sense in that context. Paul ===== # # bitblt(sm,r,dm,p,fc) # Bitmap *sm,*dm; # Rectangle r; # Point p; # int fc; # # by John F. Reiser summer 1982 # # Depending on the case at hand, generate very good code and execute it. # # offsets in a Point set x,0 set y,2 # offsets in a Rectangle set origin,0 set corner,4 # offsets in a Bitmap set base,0 set width,4 set rect,6 # parameter offsets from %fp set sm,8 set r,12 set dm,20 set p,24 set fc,28 set NREG,11 global bitblt bitblt: movm.l &0x3f3e,-(%sp) # save C registers movm.l NREG*4-4+sm(%sp),&0x001f # d1=r.o.x,,r.o.y; d2=r.c.x,,r.c.y; d4=p.x,,p.y; mov.l %d0,%a4 # sm mov.l %d3,%a5 # dm mov.w NREG*4-4+fc(%sp),%a6 # a6.w == fc movm.l rect(%a4),&0x9 # d0=sm.o.x,,sm.o.y; d3=sm.c.x,,sm.c.y; movm.l rect(%a5),&0x60 # d5=dm.o.x,,dm.o.y; d6=dm.c.x,,dm.c.y; lea.l $L50(%pc),%a0 L5: # clip r.y to sm.y mov.w %d0,%d7 # sm.o.y sub.w %d1,%d7 # - r.o.y ble.b L10 mov.w %d0,%d1 # r.o.y = sm.o.y; /* r.o.y was above sm.rect */ add.w %d7,%d4 # p.y parallels r.o.y L10: cmp.w %d2,%d3 # r.c.y : sm.c.y ble.b L20 mov.w %d3,%d2 # r.c.y = sm.c.y; /* bottom of r was below sm.rect */ L20: # clip (r.y at p.y) to dm.y mov.w %d5,%d7 # dm.o.y sub.w %d4,%d7 # -p.y ble.b L30 mov.w %d5,%d4 # p.y = dm.o.y; /* p.y was above dm.rect */ add.w %d7,%d1 # r.o.y parallels p.y L30: mov.w %d1,%d7 # r.o.y add.w %d6,%d7 # + dm.c.y sub.w %d4,%d7 # - p.y /* == max y that dm.rect allows in r */ cmp.w %d2,%d7 # r.c.y : limit ble.b L40 mov.w %d7,%d2 # r.c.y = limit L40: mov.w %d2,%d7 # r.c.y sub.w %d1,%d7 # - r.o.y sub.w &1,%d7 # /* == h-1 in bits */ blt.b ret jmp (%a0) retgen: lea.l gensiz(%sp),%sp ret8: add.l &8,%sp ret: movm.l (%sp)+,&0x7cfc rts L50: # mirror in pi/4 and reuse same code to clip x swap.w %d0; swap.w %d1; swap.w %d2; swap.w %d3 swap.w %d4; swap.w %d5; swap.w %d6; swap.w %d7 lea.l $L55(%pc),%a0 br.b L5 L55: mov.l %d1,%a1 mov.l %d4,%d6 # # So far # %d7 == h-1,,w-1 # %d6 == p.y,,p.x # %a6.w == fc # %a5 == dm # %a4 == sm # %a1 == r.o.y,,r.o.x # # Compute masks, and width in words # mov.w %d6,%d0 # p.x /* left endpoint of dst */ mov.w %d7,%d1 # w-1 add.w %d6,%d1 # right endpoint mov.l &-1,%d3 mov.l &15,%d2 and.w %d0,%d2 lsr.w %d2,%d3 # mask1 mov.l &-1,%d5 mov.l &15,%d2 and.w %d1,%d2 add.w &1,%d2 lsr.w %d2,%d5 not.w %d5 # mask2 swap.w %d5 mov.w %d3,%d5 # mask2,,mask1 asr.w &4,%d0 asr.w &4,%d1 sub.w %d0,%d1 sub.w &1,%d1 # inner-loop width in words mov.l &0,%d4 # assume LtoR mov.w width(%a5),%d3 add.w %d3,%d3 mov.w width(%a4),%d2 add.w %d2,%d2 # # So far # %d7 == h-1,,w-1 in bits # %d6 == p.y,,p.x # %d5 == mask2,,mask1 # %d4 == 0 (LtoR) # %d3.w == dm width in bytes # %d2.w == sm width in bytes # %d1.w == inner-loop width in words # %a6.w == fc # %a5 == dm # %a4 == sm # %a1 == r.o.y,,r.o.x # # If necessary, compensate for overlap of source and destination # cmp.l %a4,%a5 bne.b L80 # overlap not possible mov.l %d6,%d0 # p.y,,p.x mov.w %a1,%d0 # p.y,,r.o.x cmp.l %a1,%d0 # r.o.y : p.y bge.b L60 # if (r.o.y < p.y) mov.l %d7,%d0 # h-1,,w-1 clr.w %d0 # h-1,,0 add.l %d0,%a1 # r.o.y += h-1; add.l %d0,%d6 # p.y += h-1; neg.w %d3 # wdst = -wdst; neg.w %d2 # wsrc = -wsrc; L60: cmp.w %d7,&16 blt.b L70 # l<->r swap not needed for narrow cmp.w %d6,%a1 # p.x : r.o.x ble.b L70 # if (r.o.x < p.x) mov.l %a1,%d0 add.w %d7,%d0 mov.l %d0,%a1 # r.o.x += w-1; add.w %d7,%d6 # p.x += w-1; mov.l &-1,%d4 # RtoL swap.w %d5 # masks in other order L70: L80: # # Locate actual starting points # mov.l %d6,%d0 # p.y,,p.x swap.w %d0 mov.l %d0,-(%sp) # p mov.l %a5,-(%sp) # dm mov.l &15,%d0 lea.l $L82(%pc),%a0 # assume narrow cmp.w %d7,%d0 # w-1 : 15 ble.b L81 # guessed correctly lea.l $L85(%pc),%a0 # wide L81: mov.l %a0,-(%sp) # on return, go directly to wide/narrow code add.w %a6,%a6; add.w %a6,%a6 # with 4*fc mov.w %d1,%d7 # h-1 in bits,,inner width in words and.l %d0,%d6 # 0,,bit offset of p.x mov.l %a1,%d1 # r.o.y,,r.o.x and.w %d1,%d0 # bit offset of r.o.x sub.w %d0,%d6 # BO(p.x) - BO(r.o.x) /* amount of right rotation */ swap.w %d1 # r.o.x,,r.o.y mov.l %d1,-(%sp) # r.o mov.l %a4,-(%sp) # sm lea.l addr,%a3 jsr (%a3) mov.l %a0,%a2 # src = addr(sm,r.origin); add.l &8,%sp jmp (%a3) # %a0 = addr(dm,p); L82: mov.l &0,%d4 mov.w %d5,%d4 # 0,,mask1 swap.w %d5 # mask1,,mask2 (proper long mask; maybe 16 bits too wide) and.w %d5,%d4 # check for overlap of mask1 and mask2 beq.b L83 # no overlap ==> %d5 already correct mov.l %d4,%d5 # overlap ==> reduce %d5 by 16 bits swap.w %d5 # and put it in the proper half L83: swap.w %d7 # ,,height-1 lea.l $nrwtab(%pc,%a6.w),%a6 # -> optab tst.w %d6 # amount of right rotation bge.b L84 neg.w %d6 add.l &2,%a6 L84: add.w (%a6),%a6 jmp (%a6) nrwtab: short opMnwr-nrwtab- 0, opMnwl-nrwtab- 2 short opSnwr-nrwtab- 4, opSnwl-nrwtab- 6 short opCnwr-nrwtab- 8, opCnwl-nrwtab-10 short opXnwr-nrwtab-12, opXnwl-nrwtab-14 opMnwr: mov.l (%a2),%d0 mov.l (%a0),%d1 ror.l %d6,%d0 eor.l %d1,%d0 and.l %d5,%d0 eor.l %d1,%d0 mov.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opMnwr br ret8 opMnwl: mov.l (%a2),%d0 mov.l (%a0),%d1 rol.l %d6,%d0 eor.l %d1,%d0 and.l %d5,%d0 eor.l %d1,%d0 mov.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opMnwl br ret8 opSnwr: mov.l (%a2),%d0 ror.l %d6,%d0 and.l %d5,%d0 or.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opSnwr br ret8 opSnwl: mov.l (%a2),%d0 rol.l %d6,%d0 and.l %d5,%d0 or.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opSnwl br ret8 opCnwr: mov.l (%a2),%d0 ror.l %d6,%d0 and.l %d5,%d0 not.l %d0 and.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opCnwr br ret8 opCnwl: mov.l (%a2),%d0 rol.l %d6,%d0 and.l %d5,%d0 not.l %d0 and.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opCnwl br ret8 opXnwr: mov.l (%a2),%d0 ror.l %d6,%d0 and.l %d5,%d0 eor.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opXnwr br ret8 opXnwl: mov.l (%a2),%d0 rol.l %d6,%d0 and.l %d5,%d0 eor.l %d0,(%a0) add.w %d2,%a2 add.w %d3,%a0 dbr %d7,opXnwl br ret8 set DBR,0x51c8 set MOVLI,0x2000+074 # mov.l &..., set MOVWI,0x3000+074 # mov.w &..., set ADDWI,0x0640 # add.w &..., set FDFRAG,16 # first destination is a fragment set LDFRAG,17 # last destination is a fragment set NSHF1,18 set FD2D,19 # first destination should store 2 words set LD2D,20 # last destination should store 2 words set FSTORE,21 set DST1L,24 # dst inner count is 0 set SRC1L,25 # Nsrc is 2 set gensiz,80 widtab: mov.w %d0,(%a0)+; short 0 or.w %d0,(%a0)+; short 0 and.w %d0,(%a0)+; not.w %d0 eor.w %d0,(%a0)+; short 0 # # So far # %d7 == h-1 (bits),,w (words) # %d6 == 0,,rotate count # %d5 == mask2,,mask1 # %d4 == -RtoL # %d3.w == wdst (bytes) # %d2.w == wsrc (bytes) # %a6.w == 4*fc # %a2 -> src # %a0 -> dst # L85: lea.l $widtab(%pc,%a6.w),%a6 tst.w %d4; bpl.b L300; bset &31,%d6 L300: mov.w %d7,%d0 # inner word count bne.b L304; bset &DST1L,%d6 L304: add.w &1,%d0 # Nsrc = 1+Ninner mov.w %d0,%a1 # + ... add.w &1,%d0 # Ndst = 1+Ninner+1 add.w %d0,%d0 # magnitude of dst addressing side effects tst.l %d6; bpl.b L310 neg.w %d0; add.l &2,%a0 # RtoL L310: sub.w %d0,%d3 # compensate dst for autoincrement mov.w %d5,%d4 # mask1 swap.w %d5 # mask2 cmp.w %d4,&-1; beq.b L320; bset &FDFRAG,%d6 L320: cmp.w %d5,&-1; seq.b %d1; beq.b L330; bset &LDFRAG,%d6 L330: tst.w %d6; bne.b L360 # not NOSHIFT add.w &1,%a1 # Nsrc = 1+Ninner+1 mov.l %d6,%d0; swap.w %d0; ext.w %d0 # 0,,flag bits asr.w &1,%d7; roxl.w &1,%d0 # account for inner words odd mov.b $nstab(%pc,%d0.w),%d0 bpl.b L340; add.w &1,%d7 L340: add.b %d0,%d0 bpl.b L350; sub.w &1,%d7 L350: swap.w %d0; eor.l %d0,%d6 # the bits btst &DST1L,%d6; bne.b L355 btst &FD2D,%d6; beq.b L410 L355: ext.l %d4; bmi.b L410; swap.w %d4; not.w %d4 # NOSHIFT mask1 .l br.b L410 # NOSHIFT mask2 .l nstab: byte 0x82,0x80,0x04,0x80 # 0x80: +1 inner; 0x40: -1 inner byte 0x02,0x00,0x44,0x00 # 0x04: FD2D; 0x02: NSHF1 no first word L360: ext.w %d1; sub.w %d1,%d7 # extend inner loop mov.l &0xf,%d0 # 0 1 7 8 9 e f add.w &8,%d6 # 8 9 f 0 1 6 7 and.w %d0,%d6 sub.w &8,%d6 # 0 1 7 -8 -7 -2 -1 X=C= sign mov.w %d6,%d1; bge.b L367 # X unchanged neg.w %d1 # 8 7 2 1 X=C= 1 L367: roxl.w &1,%d1 # 0 2 e 11 f 5 3 and.w %d0,%d1 # 0 2 e 1 f 5 3 lsl.w &8,%d1 # magic position short ADDWI+001 ror.l &8,%d0 mov.w %d1,%a3 # the rotate instruction mov.l &0,%d1; not.w %d1 # 0,,-1 ror.l %d6,%d1 # where the bits are after a rotate mov.w %d1,%d0; and.w %d4,%d0; beq.b L370 # 1 src word covers dst frag not.w %d1; and.w %d4,%d1; beq.b L370 add.w &1,%a1; br.b L390 # fragment needs another src word L370: sub.w &1,%d7 # .l takes an inner word bset &FD2D,%d6 ext.l %d4; bmi.b L390 swap.w %d4; not.w %d4 # mask1 .l L390: swap.w %d1 mov.w %d1,%d0; and.w %d5,%d0; beq.b L400 # 1 src word covers dst frag not.w %d1; and.w %d5,%d1; beq.b L400 add.w &1,%a1; br.b L420 # fragment needs another src word L400: dbr %d7,L405 # .l takes an inner word clr.w %d7; br.b L420 # nothing there to take L405: L410: bset &LD2D,%d6 ext.l %d5; bmi.b L420 swap.w %d5; not.w %d5 # mask2 .l L420: tst.w NREG*4-4+fc+8(%sp); bne.b L430; bset &FSTORE,%d6 L430: mov.w %a1,%d0 # Nsrc add.w %d0,%d0 # magnitude of src addressing side effects tst.l %d6; bpl.b L431 neg.w %d0; add.l &2,%a2 # RtoL L431: sub.w %d0,%d2 # compensate src for autoincrement lea.l -gensiz(%sp),%sp mov.l %sp,%a5 swap.w %d3 swap.w %d2 cmp.w %a1,&2; bgt L445 short MOVWI+00000 mov.l (%a2)+,%d0 tst.l %d6; bpl.b L432; add.w &010,%d0 # RtoL L432: mov.w %d0,(%a5)+ mov.l &0,%d1; mov.w &-0x1000,%d2; mov.w &0100,%d3 lea.l $L438(%pc),%a1 mov.l &-1,%d0 # prepare bits to decide on "swap" tst.w %d6; bpl.b L432d; neg.w %d6 lsl.l %d6,%d0; br.b L432e L432d: lsr.l %d6,%d0 L432e: btst &DST1L,%d6; beq.b L434 bset &FD2D,%d6; bne.b L432a ext.l %d4; bmi.b L432a; swap.w %d4; not.w %d4 # mask1 .l L432a: bset &LD2D,%d6; bne.b L432b ext.l %d5; bmi.b L432b; swap.w %d5; not.w %d5 # mask2 .l L432b: and.l %d5,%d4; mov.l %d4,%d5 # single .l does it all add.l &1,%d4; beq L730 # all 32 bits sub.l &1,%d4 # need an "and" and.l %d5,%d0 cmp.l %d5,%d0 beq.b L432c short MOVWI+05300 swap.w %d0 L432c: tst.w %d6; bne L690 # and a rotate br.b L437 # NOSHIFT L434: mov.w %a3,(%a5)+ # the rotate instr short MOVWI+05300 mov.l %d0,%d1 # copy after rotate and.l %d4,%d0 cmp.l %d4,%d0 seq.b %d0; neg.b %d0; ext.w %d0 short ADDWI+000 swap.w %d0 mov.w %d0,(%a5)+ lea.l $L436(%pc),%a1 br.b L437 L436: and.w %d4,%d0 mov.w &01001,%d1; clr.w %d2; clr.w %d3 lea.l $L438(%pc),%a1 L437: br L700 L438: and.w %d5,%d0 br L545 L445: # # During compilation # %d7 == h-1,,w # %d6 == flags,,rotate count # %d5 == mask2 # %d4 == mask1 # %d3 == dst_dW,,bits for xxx.[wl] # %d2 == src_dW,,bits for mov.[wl] # %d1.w == parity # %a6 -> optab # %a5 -> next generated instruction # %a4 -> top of inner loop # %a3.w == rotate instruction # %a2 -> src # %a1 -> fragment "and" instruction # %a0 -> dst # tst.w %d6; bne.b L480 # not NOSHIFT ==> always need first word btst &NSHF1,%d6; bne.b L485 # interplay of NOSHIFT, odd, FDFRAG L480: mov.l &1,%d1 and.w %d7,%d1 # parity of inner word count lsl.w &2,%d1 # even ==> frag in %d0, odd ==> frag in %d1 bsr genwid # generate for first word and.w %d4,%d0 L485: cmp.w %d7,&2; ble.b L490 # inner dbr always falls through btst &FSTORE,%d6; beq.b L490 # no conflict "mov field" vs. %d6 short MOVWI+05300 # init inner count mov.w %a4,%d6 L490: mov.l %a5,%a4 # top of inner loop asr.w &1,%d7 # check inner word count blt.b L540 # single .l does it all bcc.b L500 # even beq.b L520 # 1 short MOVWI+05300 br.b L500 # jump into middle of inner loop add.l &1,%a4 # remember to fixup "br.b" add.w &1,%d7 # middle entry ==> no dbr offset L500: beq.b L530 # no inner words at all mov.l &4,%d1 # use %d1 in bsr.b genwid # even half of inner loop short 0 L510: mov.w %a4,%d0; neg.w %d0 bclr &0,%d0; beq.b L520 add.w %a5,%d0; mov.b %d0,(%a4)+ # fixup "br.b" into middle L520: mov.l &0,%d1 # use %d0 in bsr.b genwid # odd half of inner loop short 0 sub.w &1,%d7 # offset for inner dbr loop ble.b L530 # dbr always falls through mov.w &DBR+6,(%a5)+ sub.l %a5,%a4; mov.w %a4,(%a5)+ # dbr displacement L530: btst &LDFRAG,%d6; beq.b L540 # omit "and" for full last word mov.l &4,%d1 bsr.b genwid and.w %d5,%d0 L540: tst.w %d7; ble.b L545 # no inner loop btst &FSTORE,%d6; bne.b L545 # possible conflict "mov field" vs. %d6 short MOVWI+05300 # init inner count mov.w %a4,%d6 L545: swap.w %d3; tst.w %d3; beq.b L546 # wdst is full width of bitmap mov.w %d3,%a1 # dst_dW short MOVWI+05300 add.w %a1,%a0 L546: swap.w %d2; tst.w %d2; beq.b L547 # wsrc is full width of bitmap mov.w %d2,%a3 # src_dW short MOVWI+05300 add.w %a3,%a2 L547: mov.w &DBR+7,(%a5)+ mov.l %sp,%a4 # top of outer loop cmp.b (%a4),&0x60; bne.b L548 # not br.b mov.b 1(%a4),%d0; ext.w %d0; lea.l 2(%a4,%d0.w),%a4 # collapse branches L548: sub.l %a5,%a4; mov.w %a4,(%a5)+ # dbr displacement short MOVWI+05300 jmp (%a5) mov.w %d7,%a4 # init inner count mov.w %d7,%d6 # init inner count, 2nd case swap.w %d7 # h-1 lea.l $retgen(%pc),%a5 jmp (%sp) genwid: mov.l (%sp)+,%a1 # -> inline parameter mov.l $genget(%pc,%d1.w),%d0 tst.w %d1; beq.b L550; mov.w &01001,%d1; swap.w %d1 # parity bits L550: clr.w %d2; clr.w %d3 # .[wl] bits default to .w tst.l %d6; bpl.b L560; add.w &010,%d0 # RtoL L560: tst.w %d6; bne.b L569 # not NOSHIFT bclr &9,%d0 # NOSHIFT always %d0 mov.w (%a1),%d1; bne.b L564 # not inner loop btst &FSTORE,%d6; beq.b L562 # not "mov" mov.l &070,%d1; and.w %d0,%d1 lsl.w &3,%d1; or.w %d1,%d0 # copy RtoL mode add.w &-0x1000,%d0 # .w ==> .l mov.w %d0,(%a5)+ L561: jmp 2(%a1) genget: swap.w %d0; mov.w (%a2)+,%d0 swap.w %d1; mov.w (%a2)+,%d1 L562: mov.w &-0x1000,%d2; mov.w &0100,%d3 # .w +=> .l add.w %d2,%d0 L563: mov.l &0,%d1 # NOSHIFT always %d0 br L698 # assemble the fetch, then do the op L564: lsr.w &1,%d1; bcs.b L562 # NOSHIFT always LD2D btst &FD2D,%d6; bne.b L562 br.b L563 # alas, .w L569: mov.w (%a1),%d1; beq.b L630 # inner loop L570: lsr.w &1,%d1; bcs.b L580 # last word add.w &-0x1000,%d0 # force fetch .l mov.w %d0,(%a5)+ # the fetch .l short MOVLI+00000 mov.l %d0,%d1 swap.w %d0 clr.w %d1; eor.l %d1,%d0 # parity for mov.l %d[01],%d[10] tst.l %d1; sne.b %d1; sub.b %d1,%d0 # parity for swap.w %d[01] mov.l %d0,(%a5) # ran out of registers mov.l &0x4c80ec,%d0 # microcoded bits tst.l %d6; bpl.b L572; ror.l &1,%d0 # RtoL L572: tst.w %d6; bpl.b L574; ror.l &2,%d0 # rol L574: btst &FD2D,%d6; beq.b L576; ror.l &4,%d0 # first op .l mov.w &-0x1000,%d2; mov.w &0100,%d3 # .w +=> .l corrections L576: ror.l &1,%d0; bpl.b L578 # "swap" not needed add.l &2,%a5 ror.l &8,%d0; bpl.b L577 # existing "swap" parity OK eor.w &1,(%a5) L577: ror.l &8,%d0; bpl.b L578 # existing order OK sub.l &2,%a5 mov.l (%a5),%d0; swap.w %d0; mov.l %d0,(%a5) add.l &2,%a5 L578: add.l &2,%a5 swap.w %d1 # junk,,parity br.b L690 L580: btst &LD2D,%d6; beq.b L630 # operator .w mov.w &-0x1000,%d2 # mov.w +=> mov.l mov.w &0100,%d3 # xxx.w +=> xxx.l L630: tst.l %d6; smi.b %d1 eor.b %d6,%d1; bpl.b L650 # rotation in same direction as scan swap.w %d0 # interchange "swap" and "mov" L650: mov.l %d0,(%a5)+ swap.w %d1 # junk,,parity mov.w (%a1),%d0; lsr.w &1,%d0; bcs.b L660 # last word short MOVWI+000 mov.l %d0,%d1 eor.w %d1,%d0 mov.w %d0,(%a5)+ br.b L690 L660: tst.l %d6; bmi.b L690 # RtoL btst &LD2D,%d6; beq.b L690 # not .l tst.w %d6; bpl.b L670 # ror sub.l &2,%a5; br.b L690 # no "swap" L670: mov.w -4(%a5),(%a5)+ # extra "swap" L690: mov.w %a3,%d0 eor.b %d1,%d0 L698: mov.w %d0,(%a5)+ # the rotate instruction L700: mov.w (%a1),%d0; beq.b L730 # inner loop btst &0,%d0; bne.b L705 # last word btst &FDFRAG,%d6; beq.b L730 # no "and" L705: add.w %d3,%d0; add.w %d1,%d0; sub.b %d1,%d0 # and.[wl] %d[45],%d[01] btst &FSTORE,%d6; beq.b L720 # "mov" partial word swap.w %d0 # save the "and" short MOVWI+00000 # ,%d0 mov.w (%a0),%d6 add.w %d2,%d0 # mov.[wl] tst.l %d6; bpl.b L710; add.w &020,%d0 # RtoL; "(%a0)" ==> "-(%a0)" L710: mov.w %d0,(%a5)+ # instr to fetch memory part of word short MOVWI+00000 # ,%d0 eor.w %d6,%d0 add.w %d3,%d0; add.b %d1,%d0 # eor.[wl] %d6,%d[01] swap.w %d0; mov.l %d0,(%a5)+; swap.w %d0; mov.w %d0,(%a5)+ mov.w %d2,%d0; add.b %d1,%d0 # mov.[wl] %d[01], mov.l &-0100,%d1 # RtoL correction, if necessary br.b L770 L720: mov.w %d0,(%a5)+ # "and" for non-mov operators L730: mov.w 2(%a6),%d0; beq.b L740 # not F_CLR add.w %d3,%d0; add.b %d1,%d0 # not.[wl] %d[01] mov.w %d0,(%a5)+ L740: btst &FSTORE,%d6; beq.b L790 # non-"mov" mov.w %d2,%d0; add.b %d1,%d0 # mov.[wl] %d[01], mov.l &0100,%d1 # RtoL correction, if necessary L770: add.w (%a6),%d0 tst.l %d6; bpl.b L780 add.w %d1,%d0 # RtoL correction L780: mov.w %d0,(%a5)+ jmp 2(%a1) L790: mov.w %d1,%d0; clr.b %d0; add.w %d3,%d0 # xxx.[wl] %d[01] mov.l &010,%d1 # RtoL correction, if necessary br.b L770 # # During execution # %d[01] == rotator # %d2 [reserved for texture bits] # %d3 [reserved for texture index] # %d4 == mask1 # %d5 == mask2 # %d6.w == inner count # %d7.w == outer count # %a0 -> dst # %a1 == dst_dW # %a2 -> src # %a3 == src_dW # %a4.w == inner count init # %a5 -> retgen # %a6 [reserved for -> texture] #

2 years, 9 months

Re: [TUHS] A Reiser tour de force

by Paul Ruizendaal

>> A not-very-thorough search at tuhs turned up V9/jerq/src/lib/j/bitblt.c >> It appears to be a pre-Reiser bitblt, not what was asked for. > > > The Reiser code is in the V8 jerq tarball that Dan Cross donated: > v8jerq.tar.bz2 <https://www.tuhs.org/Archive/Distributions/Research/Dan_Cross_v8/v8jerq.tar…> > > It is in file blit/src/libj/bitblt.s (attached below for convenience). It is 750 lines of 68K assembler. It does not appear to have been ported to the Bellmac 32 CPU. Maybe it did not make sense in that context. > > Paul There also is a file “bitblt.C” in that same directory (dated May 82, versus Aug 82 for the assembler file) that seems to have a similar approach coded up in C, with a big switch where each case has a lot of “asm()” statements. It is about 400 lines long. No author is mentioned. I have not investigated deeply, but at first glance it is possible that the approach was first coded up as a kind of threaded code in C (with inline asm) and later that Summer redone as fully hand coded assembler. Just a guess. Paul ==== #include <jerq.h> #define LEFTDIR 8 #define NOSHIFT 4 #define DAMMIT 4 /* you'll see why */ #undef sw bitblt(sm,r,dm,p,fc) Bitmap *sm,*dm; Rectangle r; Point p; int fc; { register Word *source,*dest,*_source,*_dest; /* %a2-%a5 */ register UWord m,mask1,mask2; /* %d2,%d3,%d4 */ register int a,b,i; /* %d5,%d6,%d7 */ int j,h,w,dx1,sw,dw; /* clip to the destination Bitmap only */ #define rp dest #define pp source rp = (int *) &(dm->rect); pp = (int *) &p; if ((a = *rp++ - *pp++) > 0) { *(pp-1) += a; r.origin.x += a; } if ((a = *rp++ - *pp) > 0) { *pp += a; r.origin.y += a; } if ((a = r.origin.x + *rp++ - *(pp-1)) < r.corner.x) r.corner.x = a; if ((a = r.origin.y + *rp - *pp) < r.corner.y) r.corner.y = a; i = r.corner.y - r.origin.y; /* going to be h */ a = r.corner.x - r.origin.x - 1; /* going to be dx1 */ if (i <= 0 || a < 0) return; if (a < 16) goto narrow; h = i; dx1 = a; /* i and b are regs, avoid work! */ sw = sm->width << 1; /* sleazy hack to avoid shift */ dw = dm->width << 1; /* in outer, inner loops */ w = ((p.x+dx1) >> 4) - (p.x >> 4) - 1; /* inner loop */ mask1 = ~topbits[p.x & 15]; mask2 = topbits[((p.x+dx1) & 15) + 1]; if (sm == dm) { /* may have to mess with loop order */ if (r.origin.y < p.y) { /* swap top with bottom */ r.origin.y += h-1; p.y += h-1; sw = -sw; dw = -dw; } if (r.origin.x < p.x) { /* swap left with right */ fc |= LEFTDIR; r.origin.x += dx1; p.x += dx1; } } _dest = addr(dm,p); _source = addr(sm,r.origin); a = (p.x&15) - (r.origin.x&15); if (a < 0) a += 16; else /* a == 0 means no shift, remember that */ _source--; /* else grab long and shift right */ b = 16 - a; if (a == 0) fc |= NOSHIFT; source = _source; dest = _dest; switch (fc) { case F_STORE | NOSHIFT: b = w; _source++; source = _source; a = h; /* a is free => use it */ do { *dest++ = (~mask1 & *dest) | (mask1 & *source++); if ((i = b>>2) > 0) do { *((long *)dest)++ = *((long *)source)++; *((long *)dest)++ = *((long *)source)++; } while (--i > 0); if ((i = b&3) > 0) do { *dest++ = *source++; } while (--i > 0); *dest = (~mask2 & *dest) | (mask2 & *source); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--a > 0); break; case F_STORE: do { asm(" mov.l (%a2)+,%d2 # (long) m = *source++"); asm(" ror.l %d5,%d2 # rotate m right by a"); *dest++ = (~mask1 & *dest) | (mask1 & m); asm(" ror.l %d6,%d2 # rotate m right by b"); if ((i = w) > 0) do { m = *source++; asm(" ror.l %d5,%d2 # m >> a"); *dest++ = m; asm(" ror.l %d6,%d2 # m >> b"); } while (--i > 0); m = *source; asm(" ror.l %d5,%d2 # m >> a"); *dest = (~mask2 & *dest) | (mask2 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; case F_STORE | NOSHIFT | LEFTDIR: b = w; _source++; source = _source; a = h; do { *dest = (~mask2 & *dest) | (mask2 & *source); if ((i = b>>2) > 0) do { *--((long *)dest) = *--((long *)source); *--((long *)dest) = *--((long *)source); } while (--i > 0); if ((i = b&3) > 0) do { *(--dest) = *(--source); } while (--i > 0); dest--; *dest = (~mask1 & *dest) | (mask1 & *(--source)); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--a > 0); break; case F_STORE | LEFTDIR: do { asm(" mov.l (%a2),%d2 # (long) m = *source"); asm(" ror.l %d5,%d2 # m >> a"); *dest = (~mask2 & *dest) | (mask2 & m); asm(" rol.l %d5,%d2 # m << a"); if ((i = w) > 0) do { m = *(--source); asm(" rol.l %d6,%d2 # m << b"); *(--dest) = m; asm(" rol.l %d5,%d2 # m << a"); } while (--i > 0); m = *(--source); asm(" rol.l %d6,%d2 # m << b"); dest--; *dest = (~mask1 & *dest) | (mask1 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; case F_OR: case F_OR | NOSHIFT: do { asm(" mov.l (%a2)+,%d2 # (long) m = *source++"); asm(" ror.l %d5,%d2 # rotate m right by a"); *dest++ |= (mask1 & m); asm(" ror.l %d6,%d2 # rotate m right by b"); if ((i = w) > 0) do { m = *source++; asm(" ror.l %d5,%d2 # m >> a"); *dest++ |= m; asm(" ror.l %d6,%d2 # m >> b"); } while (--i > 0); m = *source; asm(" ror.l %d5,%d2 # m >> a"); *dest |= (mask2 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; case F_OR | LEFTDIR: case F_OR | NOSHIFT | LEFTDIR: do { asm(" mov.l (%a2),%d2 # (long) m = *source"); asm(" ror.l %d5,%d2 # m >> a"); *dest |= (mask2 & m); asm(" rol.l %d5,%d2 # m << a"); if ((i = w) > 0) do { m = *(--source); asm(" rol.l %d6,%d2 # m << b"); *(--dest) |= m; asm(" rol.l %d5,%d2 # m << a"); } while (--i > 0); m = *(--source); asm(" rol.l %d6,%d2 # m << b"); dest--; *dest |= (mask1 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; case F_CLR: case F_CLR | NOSHIFT: do { asm(" mov.l (%a2)+,%d2 # (long) m = *source++"); asm(" ror.l %d5,%d2 # rotate m right by a"); *dest++ &= ~(mask1 & m); asm(" ror.l %d6,%d2 # rotate m right by b"); if ((i = w) > 0) do { m = *source++; asm(" ror.l %d5,%d2 # m >> a"); asm(" not.w %d2 # m = ~m"); *dest++ &= m; asm(" ror.l %d6,%d2 # m >> b"); } while (--i > 0); m = *source; asm(" ror.l %d5,%d2 # m >> a"); *dest &= ~(mask2 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; case F_CLR | LEFTDIR: case F_CLR | NOSHIFT | LEFTDIR: do { asm(" mov.l (%a2),%d2 # (long) m = *source"); asm(" ror.l %d5,%d2 # m >> a"); *dest &= ~(mask2 & m); asm(" rol.l %d5,%d2 # m << a"); if ((i = w) > 0) do { m = *(--source); asm(" rol.l %d6,%d2 # m << b"); asm(" not.w %d2 # m = ~m"); *(--dest) &= m; asm(" rol.l %d5,%d2 # m << a"); } while (--i > 0); m = *(--source); asm(" rol.l %d6,%d2 # m << b"); dest--; *dest &= ~(mask1 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; case F_XOR | NOSHIFT: b = w; _source++; source = _source; a = h; do { *dest++ ^= (mask1 & *source++); if ((i = b>>2) > 0) do { *((long *)dest)++ ^= *((long *)source)++; *((long *)dest)++ ^= *((long *)source)++; } while (--i > 0); if ((i = b&3) > 0) do { *dest++ ^= *source++; } while (--i > 0); *dest ^= (mask2 & *source); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--a > 0); break; case F_XOR: default: do { asm(" mov.l (%a2)+,%d2 # (long) m = *source++"); asm(" ror.l %d5,%d2 # rotate m right by a"); *dest++ ^= (mask1 & m); asm(" ror.l %d6,%d2 # rotate m right by b"); if ((i = w) > 0) do { m = *source++; asm(" ror.l %d5,%d2 # m >> a"); *dest++ ^= m; asm(" ror.l %d6,%d2 # m >> b"); } while (--i > 0); m = *source; asm(" ror.l %d5,%d2 # m >> a"); *dest ^= (mask2 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; case F_XOR | NOSHIFT | LEFTDIR: b = w; _source++; source = _source; a = h; do { *dest ^= (mask2 & *source); if ((i = b>>2) > 0) do { *--((long *)dest) ^= *--((long *)source); *--((long *)dest) ^= *--((long *)source); } while (--i > 0); if ((i = b&3) > 0) do { *(--dest) ^= *(--source); } while (--i > 0); dest--; *dest ^= (mask1 & *(--source)); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--a > 0); break; case F_XOR | LEFTDIR: do { asm(" mov.l (%a2),%d2 # (long) m = *source"); asm(" ror.l %d5,%d2 # m >> a"); *dest ^= (mask2 & m); asm(" rol.l %d5,%d2 # m << a"); if ((i = w) > 0) do { m = *(--source); asm(" rol.l %d6,%d2 # m << b"); *(--dest) ^= m; asm(" rol.l %d5,%d2 # m << a"); } while (--i > 0); m = *(--source); asm(" rol.l %d6,%d2 # m << b"); dest--; *dest ^= (mask1 & m); (char *) _source += sw; source = _source; (char *) _dest += dw; dest = _dest; } while (--h > 0); break; } return; narrow: /* * width is 16 bits or less, so we can do it by reading and * writing 32 bits at a time */ _source = (Word *) sm; _dest = (Word *) dm; mask1 = ((Bitmap *) _source)->width; /* source increment */ mask1 <<= 1; /* hack to add to an address register */ mask2 = ((Bitmap *) _dest)->width; /* dest increment */ mask2 <<= 1; if (_source == _dest && r.origin.y < p.y) { /* swap top with bottom */ r.origin.y += i-1; p.y += i-1; mask1 = -mask1; mask2 = -mask2; } asm(" mov &0,%d6 # (long) b = 0"); b = topbits[a+1]; a = (16 - (p.x & 15)); /* hocus pocus to get long mask */ asm(" rol.l %d5,%d6 # (long) b <<= a"); a = 16 - a - (r.origin.x & 15); /* shift constant */ if (a < 0) { /* guess what! -1 == 63 to the 68000!!! */ fc |= DAMMIT; /* not fatal, just slow */ } source = addr(_source,r.origin); dest = addr(_dest,p); switch (fc) { case F_STORE: case F_STORE | DAMMIT: asm(" mov.l %d6,%d1 # prepare inverse mask"); asm(" not.l %d1 "); do { asm(" mov.l (%a2),%d2 # m = *source"); asm(" ror.l %d5,%d2 # rotate m right by a"); asm(" and.l %d6,%d2 # m &= b"); asm(" mov.l (%a3),%d0 # m |= *dest&~b"); asm(" and.l %d1,%d0 "); asm(" or.l %d0,%d2 "); asm(" mov.l %d2,(%a3) # *dest = m"); (char *) source += (int) mask1; (char *) dest += (int) mask2; } while (--i > 0); break; case F_OR: case F_OR | DAMMIT: do { asm(" mov.l (%a2),%d2 # m = *source"); asm(" ror.l %d5,%d2 # rotate m right by a"); asm(" and.l %d6,%d2 # m &= b"); asm(" or.l %d2,(%a3) # *dest |= m"); (char *) source += (int) mask1; (char *) dest += (int) mask2; } while (--i > 0); break; case F_CLR: case F_CLR | DAMMIT: do { asm(" mov.l (%a2),%d2 # m = *source"); asm(" ror.l %d5,%d2 # rotate m right by a"); asm(" and.l %d6,%d2 # m &= b"); asm(" not.l %d2 # m = ^m"); asm(" and.l %d2,(%a3) # *dest &= m"); (char *) source += (int) mask1; (char *) dest += (int) mask2; } while (--i > 0); break; case F_XOR: do { asm(" mov.l (%a2),%d2 # m = *source"); asm(" ror.l %d5,%d2 # rotate m right by a"); asm(" and.l %d6,%d2 # m &= b"); asm(" eor.l %d2,(%a3) # *dest ^= m"); (char *) source += (int) mask1; (char *) dest += (int) mask2; } while (--i > 0); break; case F_XOR | DAMMIT: a = -a; do { asm(" mov.l (%a2),%d2 # m = *source"); asm(" rol.l %d5,%d2 # rotate m left by a"); asm(" and.l %d6,%d2 # m &= b"); asm(" eor.l %d2,(%a3) # *dest ^= m"); (char *) source += (int) mask1; (char *) dest += (int) mask2; } while (--i > 0); break; } return; }

2 years, 9 months

Re: [TUHS] A Reiser tour do force

by Douglas McIlroy

> Does {Reiser's bitblt replacement] exist for the rest of us to study? A not-very-thorough search at tuhs turned up V9/jerq/src/lib/j/bitblt.c It appears to be a pre-Reiser bitblt, not what was asked for. But weighing in at over 800 lines of C, it vivifies the challenge that Reiser met in half the space. Doug

2 years, 9 months

LSI-11

by Jon Steinhart

Someone on another list is getting rid of one of these. Lemme know if you want it and I'll put you in touch.

2 years, 9 months

A Reiser tour de force

by Douglas McIlroy

The recent discussion about Research choosing BSD's paging over Reiser-London's brought to mind a stunning program by Reiser that Research did adopt. A critical primitive in the Blit terminal was bitblt (block transfer of a rectangular area). It was used ubiquitously, for example to refresh data when window-stacking changed, to move data within a window, or to pop up a menu.. The display memory was word-oriented, so bitblt was fraught with niggling details about bit alignment and overlap of source and destination. A general bitblt subroutine was a rats' nest of conditionals--grossly inefficient for important special cases like scrolling. Bitblt got refined (i.e. elaborated) several times before Reiser did away with it entirely. Instead he wrote a just-in-time generator of optimal code. Thousands of distinct variants, which varied in size from 16 to 72 bytes, could be produced by the same 400 lines of assembler code. Doug

2 years, 9 months

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1994

1993

1992

1991

1990

TUHS April 2022