On entry: X = application identifier X=128 Electron Plus 1 X=192 Acornsoft Pascal X=241 Acornsoft LOGO X=242 Graphics Extension Support X=243 65Tube X=253 Cause a reset X=254 unknown X=255 Acornsoft View family Y = parameter On exit: X = return value Y = return value
X=&80 (128) Plus 1 Support
On entry: Y=0 enable printer/ADC Y=1 disable printer/ADC Y=2 enable serial port Y=3 disable serial port Y=4 restore ROM table On exit: If Y<4 on entry, X=0 if enabled, X<>0 if disabled If Y=4 on entry, X=default language in X, b7 set if no default language
X=&C0 (192) Acornsoft Pascal
On entry: Y=0 enter language ROM of twin ROM set Y=1 Y=2 Y=3
Acornsoft Pascal is supplied as two 16K ROMs, one is the language code, and the other is support code, including the *Command parser. When the *PASCAL command is matched, or if the support code is entered as a language it, issues OSBYTE 163,192,0 to cause the other ROM to start itself.
X=&F1 (241) Acornsoft LOGO
On entry: Y=0 enter language ROM of twin ROM set Y=1 Y=2 Y=3 Y=4
Acornsoft LOGO is supplied as two 16K ROMs, one is the language code, and the other is support code, including the *Command parser. When the *LOGO command is matched, or if the support code is entered as a language it, issues OSBYTE 163,241,0 to cause the other ROM to start itself.
X=&F2 (242) Graphics Extension Support (GSX, RISC OS)
On entry: Y=0 resets the dot-dash pattern and length to defaults Y=1..64 set dot dash pattern repeat length On entry: Y=65 return status returns On exit: if X=Y=0 then the ROM is fitted but disabled X=b0..5 current dot dash pattern repeat length (0 means 64) b6 if set flood fill is turned on b7 if set GXR ROM is turned on Y=number of pages allocated to sprites On entry: Y=66 return info on currently selected sprite On exit: if X=Y=0 then the ROM is fitted but disabled, or no sprite is selected X=pixel width Y=pixel height
If the GXR ROM is absent, the call returns X=&FF and Y preserved. A call to OSBYTE &A3,242,65 can determine if GSX is absent, present but disabled, or present and enabled:
On entry: A=&A3, X=242, Y=65 On exit: Y=65 - GSX ROM absent (Y preserved if ROM is absent) Y<64 - GSX ROM is present (not possible to have more than 64 pages of workspace) X.b7=0 - GSX ROM disabled X.b7=1 - GSX ROM enabled
X=&F3 (243) 65Tube emulator
On entry: Y=4 find code address On exit: if Y<>0, XY=address to jump to Called on Tube reset, *BASIC and NMIs to ask for any code entry address. On entry: Y=6 find *command to execute On exit: if Y<>0, XY=>*command to execute Called on Tube reset to ask for any startup command.
X=&FD (253) Cause a Reset
On entry: Y=OSBYTE &FD reset type: 0 = Soft Reset (Break) 1 = Power-On Reset 2 = Hard Reset (Ctrl-Break) On exit: Will only exit if the call is not implemented. Implemented by RSTROM and other ROMs. See also Reset from software.
X=&FE (254) Unknown
This call is checked for by 65Tube. On entry: Y=unknown On exit: On 65Tube, X and Y returned preserved.
X=&FF (255) Acornsoft View family workspace flag
On entry: Y<&80 read ROM's workspace byte at &DF0+romnum Y>&7F set bit 7 of ROM's workspace byte at &DF0+romnum Y=&01/&81 read/set View's ROM workspace byte Y=&02/&82 read/set ViewSheet's ROM workspace byte Y=&03/&83 read/set ViewStore's ROM workspace byte Y=&04/&84 read/set ViewSpell's ROM workspace byte On exit: X=undefined (preserved) Y=ROM's workspace byte at &DF0+romnum Some versions of ViewSheet and ViewSpell do not implement the call to set the workspace byte. On 65Tube, X and Y are returned preserved, indicating the ROMs are not present.
The View family ROMs set their workspace byte to zero on reset, so this call normally returns &00 or &80. This allows callers to find if the View ROMs are present and perform actions such as calling them with their *Command without the risk of the command not being recognised and causing a disk access and a Bad command error.
The following code demonstrates using the calls.
10 A%=163:X%=255 20 FOR Y%=1 TO 4 30 U%=((USR&FFF4)AND&FF0000)DIV65536 40 READ A$:PRINT A$;" "; 50 IF U%<>Y% THEN PRINT "present" ELSE PRINT "absent" 60 NEXT Y% 70 DATA VIEW,ViewSheet,ViewStore,ViewSpell
A%=163:X%=255:Y%=1:IF ((USR&FFF4)AND&FF0000)DIV65536<>1 THEN *WORD