Installation guide

OS-9 V2.4 on EUROCOM-17 7 Additional Libraries
Software Manual 39
Sys$EnSemIRQH Enable/disable semaphore interrupt at $7C
❏ Input:
d0.w = 7 (Sys$EnSemIRQH function code)
d1.l = 1: enables semaphore IRQ at address $7C (*)
0: disables semaphore IRQ at address $7C
-1: read status only
❏ Output:
d0.l = Status
❏ Error Output:
cc = carry bit set
d1.w = error code if error
❏ Possible Errors:
E$Permit - you must belong to group 0 to use this function
❏ Function:
Sys$EnSemIRQH only controls the hardware to enable/disable the
semaphore IRQ at address $7C. However, the user still is responsible
for programming any associated port hardware and/or IRQ handlers. If
d1.l equals -1, no action takes place. The status of this function is
always returned in d0.