Host Engineering Forum

General Category => Do-more CPUs and Do-more Designer Software => Topic started by: Andrew S on August 17, 2019, 03:44:27 PM

Title: Multiple JMPs in same stage
Post by: Andrew S on August 17, 2019, 03:44:27 PM
Quick question - if there multiple JMPs in a stage, is it the first one that gets actioned?

Andrew.
Title: Re: Multiple JMPs in same stage
Post by: franji1 on August 17, 2019, 03:58:44 PM
No.  JMP does not actually cause the code to jump to that stage.  An energized JMP does 2 things, it turns ON the referenced S bit in the JMP, hence it will run the next time that SG gets executed, and it turns OFF the current stage's stage bit, so that it won't run on the next scan.  But the logic continues to execute in the current stage beyond the JMP instruction.  Hence, you can JMP to 5 different stages in one scan of a SG scan (or 3 of 5, because maybe only 3 of the 5 JMP input logic had power).
Title: Re: Multiple JMPs in same stage
Post by: Andrew S on August 17, 2019, 04:33:09 PM
That was my understanding but I somehow assumed that mutiple JMPs would be different from SGDIVRG and perhaps there was some logic to manage that (hence the question). Ok. That's good. Thanks.