msx bios

Por PingPong

Prophet (4093)

imagem de PingPong

10-03-2019, 14:43

Hi, all, i'm wondering if the msx bios is somewhat the same ( in terms of implementation of the common features, such as functions like PSGWRITE or WRTVDP etc.) between msx manufacturers or if there are differences that cause some compatibility issue (like different speed and timing of BIOS functions)?
For example the PSGWRITE on a Sony msx is exactly the same of a Philips one?

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Por Manuel

Ascended (19270)

imagem de Manuel

10-03-2019, 14:58

Por NYYRIKKI

Enlighted (6016)

imagem de NYYRIKKI

10-03-2019, 17:40

Manufacturers bought the BIOS & BASIC as is and practically newer made any changes except little localization to keyboard driver and currency. Those routines that you mention are identical in all MSX machines. How ever it should be noted that in MSX2 the SUB-ROM appeared and some of the routines were moved to there in order to free some extra space to BIOS & BASIC ROM. Because switching of ROM takes quite a bit of time there are routines that are considerably slower on MSX2 and up when compared to MSX1. For same reason MSX1 and MSX2 also differ when it comes to interrupt enabled/disabled status when returning from different BIOS routines. None of these differences are anyway related to any manufacturer though, so this is kind of offtopic.

Here is good example of such slow down case... This BASIC-program takes more than 4x longer to run on MSX2 when compared to MSX1:

10 TIME=0
20 COLOR 15,0,0
30 SCREEN 3
40 OPEN"GRP:" FOR OUTPUT AS #1
50 FOR I=2 TO 15
60 PSET (0,0),0
70 COLOR I:PRINT#1,"Hello..."
80 NEXT I
90 SCREEN 0
100 PRINTTIME