Difference between revisions of "83Plus:Hooks:9BD4"
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(→Using the Hook: Zero flag aborts, not B=0) |
m (Reverted edit of Dan Englender, changed back to last version by 84plusfreak) |
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** C holds the complement of these bits. | ** C holds the complement of these bits. | ||
* B always contains the constant 2Ch. | * B always contains the constant 2Ch. | ||
| − | * Return | + | * Return with B=0 to abort linking, similar to the [[83Plus:Hooks:9BD0|silent link hook]]. |
== Comments == | == Comments == | ||
Latest revision as of 21:28, 11 June 2005
Synopsis
Name: USB Activity Hook
Hook Pointer Block Address: 9BD4
Hook Enable BCALL: 528A
Hook Disable BCALL: 528D
Hook Call BCALL: (none known)
Hook Active Flag: 0, (iy+3Ah)
This hook is called from the interrupt routine when USB activity is detected.
Using the Hook
- The hook is called whenever any of bits 4-0 of port 55h are low.
- C holds the complement of these bits.
- B always contains the constant 2Ch.
- Return with B=0 to abort linking, similar to the silent link hook.
Comments
This hook was introduced in OS 2.30. Apps should check the OS version before attempting to use this hook.
Credits and Contributions
- 84plusfreak (Sernin van de Krol) discovered and analyzed this hook.
