Test of cycle-count macros for DOS

[dedndave]

cool - lol
i would have thought that would get you the base of the PSP or something
from what i know, org 0 sets the counter to address 0 - at least it did in 16-bit code with masm 5.10

[FORTRANS]

sorry, Michael - this machine has no floppy drive
but, Steve N. (FORTRANS) could probably test it under DOS and WIN 3.1 (WOW) for you

Hi All,

   Quick tests, prod if more wanted.

P-III Windows 2000 Command Prompt.
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits

P-III DOS 6.20 Clean Boot.
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits
0 cycles, empty
50 cycles, CtBits
42 cycles, CBits

Pentium DOS 6.20 Clean boot (regular boot locked).
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits
0 cycles, empty
39 cycles, CtBits
24 cycles, CBits


   Did not test under Win 3.11 as it did not work with the
memory managers loaded.

   And for something completely different:  This old code
does align an ORG, but with warning errors.  It looks as
if I adapted this code from something else.  I ended up
doing an ORG by hand, and not using this to avoid the
messages.

Code Select Expand


Microsoft (R) Macro Assembler Version 5.00                  10/18/9Picture File Shower                                         Page     1-3

  102 0077  1B 5B 48 24        OFF25   DB      27,'[H$'        ; Z-100 reset terminal
  103
  104                          ; buffers for data.  It was stated that these needed to be aligned on even 100H
  105                          ; boundries.  This is because of the loop counter logic being byte oriented.
  106                          IF ($-0) MOD 256
show256.ASM(98): error A2042: Constant expected
  107 0100                       org   ( $ + 256 - (($-0) MOD 256 ) )
show256.ASM(99): error A2042: Constant expected
  108                          ENDIF
  109                          ;        ORG 200H        ; Punt due to errors?
  110
  111                                                  ; High resolution buffer.
  112 0100  0200[              BUFCOL1 DB      200H DUP (?)    ; column buffers for data
  113        ??
  114             ]


HTH,

Steve N.

[FORTRANS]

cool - lol
i would have thought that would get you the base of the PSP or something
from what i know, org 0 sets the counter to address 0 - at least it did in 16-bit code with masm 5.10

Hi Dave,

   It would give the base (start) of the PSP if used in a *.COM
style program.  You would have to set up a separate segment
directive for the PSP in an *.EXE program for that to work.
(And put the ORG in that segment.) 

Regarda,

Steve N.

[dedndave]

hi Steve - interesting to see the tests
well - no matter which segment you are in, i thought ORG set the address counter
i can see how it may work differently in FLAT model programs, however
it has been so long since i have written a complicated 16-bit EXE - lol
if i remember, one of the registers has the PSP segment in it at startup (DS or ES i think - maybe both)

[FORTRANS]

hi Steve - interesting to see the tests

   Okay.

well - no matter which segment you are in, i thought ORG set the address counter

   Right.  But if you wanted to address the elements of the
PSP, for example, in an EXE program, you have to put the
ORG in the right segment.  (Well, no you don't, but then
you have have to lie to the assembler.  If I remember
correctly.)

i can see how it may work differently in FLAT model programs, however
it has been so long since i have written a complicated 16-bit EXE - lol
if i remember, one of the registers has the PSP segment in it at startup (DS or ES i think - maybe both)

   Yup, both DS and ES in an EXE.  And all four in a COM
program.

Regards,

Steve N.

[Rockphorr]

Hi
I will try it on my old p2 with win95osr2.

I use

_TEXT segment byte public 'code'

in my libs to write just after the app codeseg.

[Rockphorr]

In 16-bit code using the simplified segment directives, specifying any value greater than 2 in the align directive results in:

error A2189: invalid combination with segment alignment

I could not find any way around this short of using full segment definitions, and since I didn't want to do that, and I already had the codealign macro, I used it. The macro was actually intended for specifying alignments > 16 in 32-bit code.

The code_base label has to be at offset 0 in the code segment, and since the start of the segment is in dosctr.asm it needed to be there, and putting it there is actually more convenient.

The codealign 8 ahead of the test procedures was an afterthought that I probably should have left out. The main point is to ensure that for both procedures the call instruction has the same overhead, and I would guess that in 16-bit code an align 2 would suffice for this (or not, given that changing the loop labels in the macro from align 2 to codealign 16 made a significant difference in my tests).

Do these macros work OK on your P4, and do they work running under Windows XP?

An align for the first module segment is 16 by default.
may be a simple solution is just put an obj with code_base on fisrst place in the linker line.

[dedndave]

i always used

_TEXT SEGMENT WORD PUBLIC 'CODE'
_TEXT ENDS

with the WORD align type, you can use the EVEN directive to word-align code
it generates NOP's to align in segments with 'CODE' class
you cannot use the EVEN directive if the segment align type is BYTE
with older processors under DOS, aligning code to higher order addresses didn't make a difference
i don't know if that is true with pentiums
to 16-align the segment, you could use

_TEXT SEGMENT PARA PUBLIC 'CODE'
_TEXT ENDS

since masm version 5.10, a few parameters have been added to the SEGMENT directive

[FORTRANS]

Hi Dave,

   Just reading through a course book to find out some things
about the simplified directives, and read up on SEGMENT as well.
It said that the default alignment was PARA (16 byte) for .8086
and DWORD for .386.

Steve