11
votes
Accepted
How can I understand numerical precision of values in Microsoft BASIC (on the Dragon 32)?
Microsoft Extended BASIC, as used by the Dragon, uses a 40 bit (5 byte) float format(*1):
Field Size (Bits)
Exponent Sign 1
Exponent 7
Mantissa Sign 1
Mantissa ...
- 208k
7
votes
Accepted
How did the Dragon modify 6847 video output timing for PAL?
I used the redrawn schematics here on Github as it is difficult to read part numbers from the scans, and also it documents some detail quite well.
You are right that it does expand the line count to ...
- 27k
5
votes
How can I understand numerical precision of values in Microsoft BASIC (on the Dragon 32)?
As far as I can see, any Microsoft BASIC at that time should have used Microsoft Binary Format for floating-point numbers. Since you found out that numbers are occupying five bytes, that should mean ...
- 4,446
4
votes
How can I understand numerical precision of values in Microsoft BASIC (on the Dragon 32)?
You may want to look at the PARANOIA floating point test suite, which tests for quite a few characteristics of the floating point format and implementation (range, bits of precision, rounding, guard ...
- 18.1k
2
votes
Length of leader block in Coco and Dragon cassette tape header and .cas tape image file format
I've made a couple of discoveries after a night's sleep.
The CoCo still reads the leader length from a RAM address, but its address is two bytes higher in memory than in the Dragon 32:
0199 ** THESE ...
- 6,323
1
vote
Loading a Tandy CoCo or a Dragon 32 machine code program from cassette with multiple "name blocks"
Since the coco cassette interface used 1200 baud psk audio encoding in it, the tape format of the coco was 4X faster loading files from the tape and the tape files were 1/4th the size of similar files ...
- 51
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