Coding - On yet another way to the fort-like coding.
■ ■ ■ ■ ■ ■ ■ ■ ■ ■
■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■
On yet another way to the fort-like coding
Echo35 (2:5029 / 35.26) ZX.SPECTRUM
Msg: 447 of 547 -401 Snt Pvt Loc
From: Dima Bystrov 2:5029 / 35.26 16 Jan 2003 17:44:07
To: Nick Sevryukov 16 Jan 2003 18:41:12
Subj: Re: FORTH
Hello Nick!
14 Jan 2003 12:58, Nick Sevryukov wrote to Valerij Kozhevnikoff:
VK>> Here are just a stack to be looked after. And then recover
VK>> if necessary.
VK>> All depends on how often and how is it called and how
VK>> must be
VK>> stack all the time.
NS> The main thing is that it makes all the prog Nitak wrong.
You NS> actually copied, only the last command jp (hl).
NS> Read what I wrote earlier in the notes to the way it is
NS> should work.
NS> This piece is often enough to spoil and a stack of very
NS> desirable! Simply, he (the stack) is used actively.
[Skip]
NS> Or you can arrange for another, only to remember that
NS> have an array of addresses, which is posedovatelno
NS> transition and a pointer to be automatically
NS> rise to the following address (see above).
there are more crazy idea:)
does not have an array of addresses, and with JP ...
a first approximation, it seems that there some losses, but it
is not so! let the HL will be the current address (similar to
(SP), but without treatment to the stack)
why it is profitable to HL, in the course text will be
appreciated:)
"Larry is as follows:
inc hl, hl, hl
...
jp (hl)
(+ JP = 18 +4 +10 = 32 clocks)
(For comparison, call + ret = 27 cycles)
best inc hl, hl, hl place at the beginning of subroutine
with jp (hl) - in the end.
if hl is vital, it can be
push hl
...
pop hl
or (simultaneously with the readout parameter from the stack)
ex (sp), hl
...
pop hl
or (in conjunction with zapihivaniem result in a stack)
push hl
...
ex (sp), hl
(And other variations)
(A conventional method, a call-ret, is difficult
use the data stack
inside a subroutine, call-ret loses about 40 cycles:
ex (sp), hl: ld (exit +1), hl: pop hl, de ... exit: jp 0)
between the jp-s can be inserted pieces of conventional
mashkoda (plain code), but we must not forget to restore hl.
for example:
ld hl, $ +6
jp kudato +3
thus skipped inc hl, hl, hl.
or even
ld l, $ +5; h was equal to the old
jp kudato +3
if we assume that the run-time "shell" that
method and the classic is not just about concede to each other,
then there ^ ^ ^ on this piece of plain code we win 8 or 11
bars! (By length is obtained by losing 02.03 bytes) in this
case of (those same team) can be written even design plain
code; call; goto! (Won by about 18 cycles and an average nibble)
so looks like goto in the normal case:
jp metka
ld hl, kuda
jp (hl)
In fact, this record will never need, since case
where to goto is plain code, we have discussed, so we consider
case where the call is to goto:
ld hl, kuda; or ld l
jp metka +3
(Not quite a logical order, but to write such a compiler can)
then winning 8 beats (or 11) and, if lucky, a byte.
Now consider konktruktsiyu call with a numeric parameter
in ordinary life is ld de, param: call metka
but we will have
jp metka
dw param; so you can make a lot of options
...
metka
inc hl, hl, hl
ld c, (hl)
inc hl
ld b, (hl)
inc hl
...
(Of course, the option to ld is also possible, but it is rarely
beneficial)
conditional branch can be written as:
jp jpZ
dw kuda
...
jpZ
inc hl, hl, hl
jr z, jpZyes
inc hl, hl
jp (hl)
jpZyes
ld a, (hl)
inc hl
ld h, (hl)
ld l, a
jp (hl)
or, if speed is important,
jp z, kuda
ld hl, $ +3; or ld l, $ +2
...
kuda
ld hl, $ +3
(Then losing 6.5 bytes instead of 2)
loop with a precondition:
on an ordinary ACME writes:
<...>
jp while
loop
while
jp cc, loop
<...>
but we will have (if we assume that <...> was call metka, and
was call metka2):
ld hl, while; or ld l
jp metka +3
loop
ld hl, $ +6; or ld l, $ +5
jp metka2 +3
<More body>
while
jp cc, loop
ld hl, $ +6; or ld l, $ +5
[Call metka3 +3]
(Gain in speed of approximately 9 cycles per iteration of the
loop, loss of $ 5.4 B)
intermediate result calculations shall be in the de
For example, the expression with the addition of:
push de
pop hl
add hl, de
ex de, hl
ld hl, $ +3
or subtraction:
push de
pop hl
or a
sbc hl, de
ex de, hl
ld hl, $ +3
or shorter, but more slowly (so you can record and any other
operation):
push de
jp subpp
...
subpp
inc hl, hl, hl
ex (sp), hl
or a
sbc hl, de
ex de, hl
pop hl
jp (hl)
maybe 2 spetsvyzova - jp (ix) and jp (iy), for something very
frequent
In general, it is less a fort, and the "alternate coding";)
- Alone Coder [ZX-Guide] [Inferno] [AlCoNews] [ACEdit] [PT]
[Chip] [STS] [ANSI] [8col] [UNRAR]
--- GoldED/386
* Origin: The queue is in the store, "said T (c) S,-and this
is SHOT
::::::::::::::::::::::::::::::::::::::::::::::::::
::::::::::::::
--------* List Honored Neispolzovateley AC Edit *-------
1) Pawel / Real_soft Paul Kislyak 2:454 / 11.25
2) Kurleson / HorrorSoft Alexey Kravchenko 2:5068 / 6
3) SirX Sergei G. Shelginsky sirx@atnet.ru
Arkhangelsk Region., Severodvinsk, ul.Zh / Dorozhnaya 35-51
(818-4) 55-10-89, 8-921-670-02-85
4) Alex_Xor / PSV Alexander D. Shushkov axor@mail.ru
(8172) 25-28-71, 160035 Vologda POBox 136
5) Diver/4d Alex Golubtsov orangefox@mail.ru
6) Noviset / Brutal_Creators Igor Shakhov [2:5050 / 109.52]
----------* List Honored Members AC Edit *---------
Honorary and eternal:
1) Nikphe Aleksey Emelyanov
391420 Ryazan region., Chuchkovsky rn, p.Avangard, Ruleznaya 12
2) Mr.Event Alexander Lesovskaya
391420 Ryazan region., Chuchkovo, Kalinin, 26 (8-238)
07/10/1973 3) CyberDemon Maxim Mit'kin 2:5029 / 35.18
Ryazan, ul.Novoselov, 50k2-197
4) Basil Basil E. Loginov, 390035 Ryazan, Poletaeva ,15-5
5) John_Silver Denis E. Loginov there:)
6) TS Sergey Tyurin triod@aport2000.ru
390029 Ryazan, High-,16-53 (0912) 75-40-74
8-903-640-01-49
7) U # 74 Sergey Machines u_74@mail.ru
443065 Samara, Pugachevskiy_trakt d.66 kv.3
8) Shaitan / SoK Maxim Shashkin 2:5057 / 21.36 (8462) 34-82-92
9) Dissonator Constantine Shaev
390048 Ryazan, ul.Zubkovoy ,19-106 (0912) 41-03-50
10) Way of the Samurai, Alexander Golovanov [aiki@mail.nnov.ru]
11) Dark Raven Semen Tsehmeyster
187500, Leningrad Region. g.Tihvin Mashinostroiteley 44, kv.151
12) Disabler / DPL Andrey Gorelov
344045 Rostov-on-Don ul.Mironova 3 / 3, kv.120
13) Max / Cyberax / BDA Maxim Arnold [amv@kuzbass.stack.ru]
Other:
1914) Stormbringer / Cobra_Soft Valera Selev 2:462 / 162.7
79022 Ukraine, Lviv-22, PO Box 798
15) AmoNik Nikolai Amosov 2:5030 / 978.14, 500:812 / 2.26
(SPbZXnet) 16) Macros Sergei Gulyaev zxmsf@mail.ru
17) Jerri / AF Yuri Potapov, 2:5057 / 21.89 (8462) 92-73-26
18) Ldir / mp., I8 Jaroslav Turbin (0912) 77-40-37
last_128@mail.ru 390000 Ryazan Pervomajskij Ave 40k.1, kv.18
19) Chapay / mp. Viktor Spiridonov (0912) 76-07-36
mir_tut@mail.ru 390029 Ryazan ul.Stroiteley 1, kv.10
1920) Voodoo / Delirium_Tremens Dmitry Voo vooha@ua.fm
21) Risk / O
Other articles:
|
|
|
|
Coding - On yet another way to the fort-like coding.
|
