Installation guide

OS-9 V2.4 on EUROCOM-17 7 Additional Libraries
Software Manual 33
Sys$IOS Get mmu-protected I/O segment
❏ Input:
d0.w = 0 (Sys$IOS function code)
d1.l = 1: request I/O segment
0: return I/O segment
d2.l = size of I/O segment
(a0) = address of segment requested
❏ Output:
none
❏ Error Output:
cc = carry bit set
d1.w = error code if error
❏ Possible Errors:
E$Permit - you must belong to group 0 to use this function
E$MemFull, E$NoRAM
❏ Function:
Sys$IOS is used in systems equipped with a paged memory
management unit (PMMU) and thereby using the system security
module (SSM). This function enables group 0 user programs to perform
memory mapped I/O, i.e. writing patterns into a video RAM located
outside the process memory.
❏ Cross Reference:
see F$Permit