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epsilon

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Joined: 30/07/2020
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Posted: 03:46pm 12 Nov 2020

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Hi all,

Is there a way to invoke the TEXT command from a CSUB?
I don't see any candidates in ARMCFunctions.h (FW ver 5.05.05).

TEXT X, Y, STRING, ALIGNMENT, FONT, SCALE, C, BC

Thanks for any help,
Epsilon/Ruben.

Epsilon CMM2 projects

matherp
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Joined: 11/12/2012
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Posted: 04:28pm 12 Nov 2020

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If you download and install RC17 again there is now support for a call to RunBasicSub
This allows you to create a C string which contains any Basic command and then execute it from a C Function. This idea was created for the PICs by Geoff and I personally have never used it and it is completely untested on the CMM2

IMPORTANT the C string must be terminated by two zero characters and not just one
Edited 2020-11-13 02:33 by matherp

lizby
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Joined: 17/05/2016
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Posted: 05:51pm 12 Nov 2020

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matherp said RC17 ... RunBasicSub ... This allows you to create a C string which contains any Basic command and then execute it from a C Function. This idea was created for the PICs by Geoff and I personally have never used it and it is completely untested on the CMM2

Can you explain this more fully or link to an explanation?

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epsilon

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Posted: 05:58pm 12 Nov 2020

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Thank you for the quick response Peter. Do you know if RunBasicSub has access to the environment from which the calling CSUB was invoked, i.e. can I reference MMBasic locals and globals in that C string, or should I stick to immediates only?

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matherp
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Posted: 06:56pm 12 Nov 2020

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Quote Do you know if RunBasicSub has access to the environment from which the calling CSUB was invoked, i.e. can I reference MMBasic locals and globals in that C string, or should I stick to immediates only?

Why not try it and see. Start simple and see what, if anything, works

epsilon

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Posted: 11:08am 03 Mar 2021

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matherp said
If you download and install RC17 again there is now support for a call to RunBasicSub
This allows you to create a C string which contains any Basic command and then execute it from a C Function. This idea was created for the PICs by Geoff and I personally have never used it and it is completely untested on the CMM2

I finally gave this a try and am happy to report that it's working well.

I'm making a call-out from a CSUB to an MMBasic SUB and pass along one parameter.

The MMBasic code looks like this:

DIM wm_draw_callout_arg%

SUB WM_DRAW_OBJ_DRAW_CALLOUT
Object_draw(wm_draw_callout_arg%, 1)
END SUB

CSUB wm_draw_csub INTEGER, INTEGER, STRING, INTEGER
00000000
4FF0E92D F44F4C96 68097A48 0B00F04F 68066824 68E06825 FA06FB0A 07C1EB05
00C6EB00 8B02ED2D 921
...
END CSUB

wm_draw_csub updates_lid%, wm_view%, "WM_DRAW_OBJ_DRAW_CALLOUT"+CHR$(0), wm_draw_callout_arg%

The call-out in the C code looks like this:

#include "ARMCFunctions.h"
...
void wm_draw_csub(long long *updates_lidp, long long *wm_viewp, char *callout_sub, long long *callout_arg) {
...
*callout_arg = current_object;
RunBasicSub(callout_sub+1);
}

A few details to keep in mind:
- The string referencing the Basic sub has to be all capitals.
- You have to append an additional 0 to that string. That was mentioned before.
- In the C code, add one to the string pointer. MMBasic strings have the string length in the first byte, C strings don't, so you have to move the point past that first byte.
- You can't just do this:

RunBasicSub("WM_DRAW_OBJ_DRAW_CALLOUT\0");

The C compiler would put the string literal in the data segment and that doesn't get included in CSUBs. There might be a way around this. I vaguely remember the original CSUB/CFunction thread talked about it. I prefer passing in the string.

Epsilon CMM2 projects

thwill

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Joined: 16/09/2019
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Posted: 07:20pm 03 Mar 2021

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Quote Please tell me that this is a problem with a known solution ... and point me at that solution.

For example if necessary can we do this:

char foo[] = "foo";

and then use variable foo instead of literal "foo".

As my understanding is that this should cause the generated binary to store "foo" on the stack and not in a read-only data section.

Best wishes,

Tom
Edited 2021-03-04 05:48 by thwill

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matherp
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Posted: 07:45pm 03 Mar 2021

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Quote Please tell me that this is a problem with a known solution ... and point me at that solution.

See my second post here

thwill

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Posted: 11:46pm 03 Mar 2021

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matherp said

Quote Please tell me that this is a problem with a known solution ... and point me at that solution.

See my second post here

Thanks Peter. Looks "odd"

, but if it works then who am I to complain.

Best wishes,

Tom

MMBasic for Linux, Game*Mite, CMM2 Welcome Tape, Creaky old text adventures

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