SymbOS MSX multitasking operating system - help needed!

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By ARTRAG

Enlighted (6188)

ARTRAG's picture

09-05-2006, 17:34


Is the VDP in transparent mode as fast as in normal mode?

transparent mode is fast as any other logical copy i.e. like a (dead) snail

on the other side, fast copy is limited to bytes, so, in sc5, you cannot use it when x
coordinate is odd, or the x coordinate is even but the width is odd

even worst in sc6, where you need x be multiple of 4

By Prodatron

Paragon (1788)

Prodatron's picture

09-05-2006, 17:42

Today I ported the device manager module to the MSX successfully with the exception of the RTC. Does anyone have a hint, what is the easiest way to detect a present RTC?
Currently I don't know, if there is any standard proportional mouse for the MSX available. Any hints here?

By Prodatron

Paragon (1788)

Prodatron's picture

09-05-2006, 17:45

Sorry, again I asked too fast again. I will write/read the "scratch" byte in block 2.

By Prodatron

Paragon (1788)

Prodatron's picture

09-05-2006, 18:05

transparent mode is fast as any other logical copy i.e. like a (dead) snail

Hm, any idea how many micro seconds it (more or less exactly) takes to copy a 8x8 pixel block inside the VRAM with logical copy?

By ARTRAG

Enlighted (6188)

ARTRAG's picture

09-05-2006, 18:16

time depends on the active screen and on the orizontal width of the block
(and on the refresh rate 50/60Hz and on the sprite active and on the moon phase..)

given the screen and the logical operation,

a 16x4 block is faster than a 8x8

you can assume a formula like

T = a* dx*dy + b*dx

where a and b depends on the screen mode on the logical operation

go here for measures

http://map.tni.nl/articles/vdp_commands_speed.php

By Prodatron

Paragon (1788)

Prodatron's picture

09-05-2006, 18:23

Yes, I saw the test results on this page, I just don't know, what kind of blocks he filled/copied.
For proportional text output I will need to copy (logical) single W x 8 blocks for each char, where W is between 1 and 8. I am sure, normally you would use byte copy, if the text is not proportional, so I wonder, if in my case it won't be too slow at the end.

By ARTRAG

Enlighted (6188)

ARTRAG's picture

09-05-2006, 18:32

I've no fresh data, sorry

By flyguille

Prophet (3029)

flyguille's picture

09-05-2006, 18:41

transparent mode is fast as any other logical copy i.e. like a (dead) snail

Hm, any idea how many micro seconds it (more or less exactly) takes to copy a 8x8 pixel block inside the VRAM with logical copy?

good enough just for typing and showing littles sentences at a time....

very slow for re-drawing all a window at a PAINT event

the vdp allow to do scrooling by itself so that helps, but clipping at the same time is a lot of work for only the CPU taking including seconds to do that.

a fast way is prebuffering but that eats a lot of RAM but it is clean, easy and faster.

By Manuel

Ascended (15531)

Manuel's picture

09-05-2006, 18:55

The clock chip is on every MSX2. See also http://map.tni.nl/resources/
and http://map.tni.nl/resources/msx_io_ports.php

By Prodatron

Paragon (1788)

Prodatron's picture

09-05-2006, 19:34

good enough just for typing and showing littles sentences at a time....
very slow for re-drawing all a window at a PAINT event

Hm, bad news. Maybe I should prepare a line of proportional text in the CPU memory and copy it with "vram write" or the "highspeed put byte" command into the vram? Did someone already write a fast proportional text output routine? Just want to know, if it is somehow possible...

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