May 2017 - Oberon - mailman3.inf.ethz.ch

FPGA Oberon - Definition Module Tool
by thomas.kral＠email.cz 08 Oct '18

08 Oct '18

Hi, I am thinking of a simple tool that could extract definition info from *.Mod and produce respective *.Def file. Definition files can be quickly looked at, to remind a programmer of the interface *.Mod modules export. While on Linux one could use grep $ grep PROCEDURE\ * *.Mod.txt to obtain info at least about procedures, but how about exported types and variables? I am looking for a recommended way how to simply code such a tool, is it a good idea to use `ORP' parser somehow for the task? I prefer to code it simple, does not have to be perfect, but should carry the idea. Tomas

5 11

FPGA - Save / Restore OBERON.FS
by Andreas Pirklbauer 22 Jul '17

22 Jul '17

There will be an enhanced Oberon file system in Experimental Oberon offering, amongst other things, larger file sizes.________________________________________ > From: Skulski, Wojciech skulski at pas.rochester.edu > Sent: Thu Apr 20 06:42:54 CEST 2017 > My biggest concern about Oeron FS is its limited size. > Wojtek

4 10

Fwd: Re: FPGA - RISC multiply/divide
by Walter Gallegos 30 May '17

30 May '17

Tomas, No magic, moderns FPGA have DSP blocks with dedicated hardware multipliers in silicon, on the other hand division need be implement into the logic farm; using one of the well know algorithms to keep logic resources within reasonable limits. Simulator waveforms show the process, 11 divided by 3, quotient = 3 remainder = 2; one clock period for bit. In practise, one clock for setting up values, results can be read one clock after calculus done; so, divide a 32 bit number use 34 clocks. Waveforms correspond to our own VHDL version of RISC-5. Walter, El miércoles-2017-05-24 a las 13:21, Tomas Kral escribió: > Hi, > > This example of binary multiply needs >>>fixed size font<<< to display > properly. > > [a] Shift & addition > > 0101 =5(4+1) > 0101 x =5(4+1) > _________ > > 0101 > 0000 shift > 0101 shift > _________ > add above > 011001 =25(16+8+1) > > > [b] Repeated addition, 5+5+5+5+5 > > 0101 > 0101 > 0101 > 0101 > 0101 > __________ > > 011001 =25(16+8+1) > > > To multiply 32 bit integers upto 32 cycles are needed. There is some > FPGA magic used, to complete each `MUL'tiply in two cycles only. > > How many cycles does `DIV'require? > Looking for the above analogy. > > Tomas > > > On Tue, 23 May 2017 12:36:04 +0200 > Tomas Kral<thomas.kral(a)email.cz> wrote: > >> Hi Joerg, >> >> Multiplication ~ repeated addition >> Division ~ repeated subtraction >> >> That is a simplification but is not the way implemented in RISC. >> Consider 65536 DIV 1, that would require 65536 iterations. >> >> Instead shift (left | right) + (add | sub) is used for DIV and MUL. >> This requires much fewer iterations. >> >> My argument is right about the example given in the 16.2.3. >> >> 14 DIV 4, is 3 with remainder 2 >> >> But the example gives 4 and the remainder 2 >> >> Tomas >> >> >> On Tue, 23 May 2017 11:23:14 +0200 >> Jörg<joerg.straube(a)iaeth.ch> wrote: >> >>> Tomas >>> >>> http://www.homeschoolmath.net/teaching/md/division-repeated-subtraction.php >>> >>> Jörg >>> >>>> Am 23.05.2017 um 11:09 schrieb Tomas Kral<thomas.kral(a)email.cz>: >>>> >>>> Hi, >>>> >>>> I am reading chapters on RISC implementation. I managed to >>>> understand multiplication - `MUL' instruction, consisting of >>>> shifting x and adding y to the product. >>>> >>>> I seem not understanding the division, chapter 16.2.3. >>>> In the example for x=14, y=4 gives quotient q=4, and the remainder >>>> r=2. >>>> >>>> But... >>>> q = x DIV y = 3, r = x MOD y = 2 >>>> ??? >>>> >>>> -- >>>> Tomas Kral<thomas.kral(a)email.cz> >>>> -- >>>> Oberon(a)lists.inf.ethz.ch mailing list for ETH Oberon and related >>>> systemshttps://lists.inf.ethz.ch/mailman/listinfo/oberon >> >

3 5

Ethernet card rtl8139 [1] trap -14 pl3 A2 revision 1749 (02.12.2008) error
by roeulew＠gmail.com 27 May '17

27 May '17

The card is enabled but not connecting to the home site getting site not found please advise how to correct this problem Sent from Mail for Windows 10

1 0

Re (2): A test.
by peter＠easthope.ca 25 May '17

25 May '17

> Always check whether the variables you use need to be initialized. Thanks for the help. Fortunately there is progress between the mental blocks. Regards, ... Lyle E. -- 123456789 123456789 123456789 123456789 123456789 123456789 123456789 Tel: +1 360 639 0202 Pender Is.: +1 250 629 3757 http://easthope.ca/Peter.html Bcc: peter at easthope. ca

1 0

FPGA - Bitmap Replace Horizontal Line
by Tomas Kral 24 May '17

24 May '17

Hi, I was scratching my head over how to implement the `replace' mode. Seems more complicated than `invert' mode, which only applies `/' set operator in place of `+' in the PaintHLine.Mod (see earlier post) I thought to erase destination rectangle with $0000$ first than paint bitmap in the cleared area. To erase destination rectangle, appears to be done in two steps, paint black rectangle, then invert it. The replace mode can be done in three steps: [a] paint black rectangle [b] invert black rectangle [c] paint bitmap in the cleared area The above replace mode performs 3 times worse to Paint/Invert modes. What do you think? -- Tomas Kral <thomas.kral(a)email.cz>

5 9

FPGA - RISC multiply/divide
by Tomas Kral 24 May '17

24 May '17

Hi, I am reading chapters on RISC implementation. I managed to understand multiplication - `MUL' instruction, consisting of shifting x and adding y to the product. I seem not understanding the division, chapter 16.2.3. In the example for x=14, y=4 gives quotient q=4, and the remainder r=2. But... q = x DIV y = 3, r = x MOD y = 2 ??? -- Tomas Kral <thomas.kral(a)email.cz>

2 3

A test.
by peter＠easthope.ca 23 May '17

23 May '17

Hi, This module compiles in Oberon in LinuxAos (rev.6661). MODULE Test IN Oberon; IMPORT Texts, Oberon; VAR Wr: Texts.Writer; PROCEDURE Test*; BEGIN Texts.WriteString(Wr, "A line."); Texts.WriteLn(Wr); Texts.Append(Oberon.Log, Wr.buf) END Test; BEGIN END Test. Executing Test.Test gives http://easthope.ca/Trap. Reinstalling the system is the only option I think of. Any ideas? Thanks, ... Lyall E. -- 123456789 123456789 123456789 123456789 123456789 123456789 123456789 Tel: +1 360 639 0202 Pender Is.: +1 250 629 3757 http://easthope.ca/Peter.html Bcc: peter at easthope. ca

2 1

FPGA - SET initialisation
by Tomas Kral 22 May '17

22 May '17

Hi, Reading `SET - neglected data type', I was wondering, how I could best initialise a SET variable. VAR b: BYTE, i: INTEGER, s: SET; ... SYTEM.GET(adr, s); (* reading 4 bytes from adr, easiest but adr MOD 4! *) ... SYTEM.GET(adr, i); s := {i}; (* same result as above? *) ... (* provided adr MOD = 0 *) SYTEM.GET(adr+0, b); s := {b}; (* same result as above? *) SYTEM.GET(adr+1, b); ASL(s,8); s := s + {b}; SYTEM.GET(adr+2, b); ASL(s,8); s := s + {b}; SYTEM.GET(adr+3, b); ASL(s,8); s := s + {b}; Tomas

4 12

Modulus on negative number
by Tomas Kral 17 May '17

17 May '17

Hi, EDIT - the reason I ask, is that until now I thought that a remainder is a computing synonym for the modulus. Also, I remember that one of the early Intel processors had problems with zero division, but some maths people argued that it was alright as zero division depends on the rate of convergence. But Maths was never my cup of tea. At last I took some interest in this MOD'ulus discussion. I wonder how it is (un)defined in Math / Oberon x DIV 0 0 MOD x Tomas On Mon, 15 May 2017 09:57:08 +0200 Jörg <joerg.straube(a)iaeth.ch> wrote: > It is. MOD is defined as C x C -> C > Jörg > > > Am 14.05.2017 um 20:17 schrieb Aubrey McIntosh > > <aubrey.mcintosh(a)utexas.edu>: > > > > I have not checked my number theory book lately, but I don't think > > (i.e., don't remember) that it is defined mathematically for > > negative divisors either. > > > >> On Sat, May 13, 2017 at 3:12 AM, Peter Matthias > >> <PeterMatthias(a)web.de> wrote: Agreed. However, -1 MOD -12 or 1 MOD > >> -12 is not defined in Oberon. > >> > >> > >>> Am 12.05.2017 um 22:43 schrieb Aubrey McIntosh: > >>> for -1 MOD 12, the mathematically correct answers which are > >>> consistent with the language report, are > >>> q=-1, r=11. > >>> > >>> This definition works very well, for example, to implement wrap > >>> around strip chart displays. > >>> > >>> > >>> On Fri, May 12, 2017 at 2:28 PM, Peter Matthias > >>> <PeterMatthias(a)web.de <mailto:PeterMatthias@web.de>> wrote: > >>> > >>> Warming up the thread to give supposedly correct answer: > >>> > >>> Am 16.02.2017 um 00:00 schrieb Peter Matthias: > >>> > >>> > >>> > >>> Am 15.02.2017 um 04:21 schrieb Srinivas Nayak: > >>> > >>> Dear All, > >>> > >>> Recently I come across modulus on a negative number. > >>> Will it produce a negative number or positive? > >>> Someone says both are correct! > >>> http://stackoverflow.com/a/4403556 > >>> <http://stackoverflow.com/a/4403556> > >>> Which one is mathematically correct? > >>> Surprisingly different languages calculate it > >>> differently even! What is Oberon's way? > >>> > >>> > >>> The theory was already answered. In practice, all compiler > >>> implementations I used (native X86, Shark, MIPS), give > >>> wrong result when > >>> both, divident and divisor are negative. I fixed it just > >>> yesterday for > >>> all non x86 versions. > >>> > >>> > >>> I should have read the language report before making such > >>> claims. > >>> > >>> Oberon Report says: > >>> > >>> "The operators DIV and MOD apply to integer operands only. > >>> They are related by the following formulas defined for any > >>> dividend x and positive divisors y: > >>> x = (x DIV y) * y + (x MOD y) > >>> 0 ≤ (x MOD y) < y" > >>> > >>> Oberon07-Report says: > >>> > >>> "The operators DIV and MOD apply to integer operands only. > >>> Let q = x DIV y, and r = x MOD y. > >>> Then quotient q and remainder r are defined by the equation > >>> x = q*y + r 0 <= r < y" > >>> > >>> Last statement obviously cannot be met if y is negative. > >>> > >>> So in short: Don't use DIV/MOD for negative divisors as the > >>> result is not defined. > >>> > >>> >From the implemtation point of view this perfectly makes > >>> >sense as > >>> negative divisors are seldom used and correction for DIV of > >>> the usually stupid hardware implementation only takes 3 additional > >>> instructions compared to at least 6 for a complete definition. > >>> Simple SHIFT/AND instructions for power of 2 divisors easily > >>> outwight these 3 additional instructions. > >>> > >>> > >>> Peter > >>> > >>> -- > >>> Oberon(a)lists.inf.ethz.ch <mailto:Oberon@lists.inf.ethz.ch> > >>> mailing list for ETH Oberon and related systems > >>> https://lists.inf.ethz.ch/mailman/listinfo/oberon > >>> <https://lists.inf.ethz.ch/mailman/listinfo/oberon> > >>> > >>> > >>> > >>> > >>> -- > >>> Aubrey McIntosh, Ph.D. > >>> 1502 Devon Circle > >>> Austin TX 78723 > >>> (512) 348-7401 > >>> > >>> > >>> > >>> -- > >>> Oberon(a)lists.inf.ethz.ch mailing list for ETH Oberon and related > >>> systems https://lists.inf.ethz.ch/mailman/listinfo/oberon > >>> > >> -- > >> Oberon(a)lists.inf.ethz.ch mailing list for ETH Oberon and related > >> systems https://lists.inf.ethz.ch/mailman/listinfo/oberon > > > > > > > > -- > > Aubrey McIntosh, Ph.D. > > 1502 Devon Circle > > Austin TX 78723 > > (512) 348-7401 > > > > -- > > Oberon(a)lists.inf.ethz.ch mailing list for ETH Oberon and related > > systems https://lists.inf.ethz.ch/mailman/listinfo/oberon -- Tomas Kral <thomas.kral(a)email.cz> -- Oberon(a)lists.inf.ethz.ch mailing list for ETH Oberon and related systems https://lists.inf.ethz.ch/mailman/listinfo/oberon -- Tomas Kral <thomas.kral(a)email.cz>

4 7