GMC-4: how CAL SIFT works?

category: code [glöplog]

I am studying GMC-4 commands, it is not clear to me how this command works? The description says "If the original value is an even number, then the execution flag is 1. If it is an odd number, then the execution flag is 0". In the source code of the emulator, the flag F is defined as Ar & 1.

Are there any computer owners who will demonstrate how the opcode works?

added on the 2021-10-03 11:45:38 by g0blinish

If the question is whether the LSB dropping out with the shift goes into the flag inverted or not:
this page from the manual of the Science Fair Microcomputer Trainer agrees with page 103 of Gakken's original FX-Maikon R-165 manual.

Seems like it does get inverted. =)

added on the 2021-10-03 14:14:55 by Krill

Found here:

Code:

	// Ar>>1->Ar, !carry->exec
	bool rtn = (vm.RegA() & 1)? false : true;

added on the 2021-10-03 14:27:43 by Krill

good to check on real

added on the 2021-10-03 15:19:31 by g0blinish

pouët.net

GMC-4: how CAL SIFT works?

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