Texas Instruments TI-89 Developer's Guide

632
Appendix A: System Routines — Interrupts
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
OSSetSR
Declaration:
WORD
OSSetSR
(WORD
InterruptLevel
)
Category(ies):
Interrupts
Description:
Sets the 68000 status register to block all interrupts at and below
InterruptLevel
.
Inputs:
InterruptLevel
— One of:
0x0700 — Block all interrupts
0x0600 — Block
´
key and below
0x0500 — Block Timers and below
0x0400 — Block Link and below
0x0300 — Block Slow Clock (not implemented) and
below
0x0200 — Block Keyboard and below
0x0100 — Block key scan
0x0000 — Enable all interrupts
Outputs:
Previous mask value.
Assumptions:
The 68000 status register is set to
InterruptLevel
and 0x0F00.
Side Effects:
The calculator is normally set to run with interrupts enabled. The previous
value of the interrupt mask should always be restored prior to swapping out
or exiting. Setting an interrupt mask above 0x0500 will disable the
calculator’s ability to save state on power outage, and is discouraged.
Availability:
All versions of the TI-89 / TI-92 Plus.
TI-89 / TI-92 Plus
Differences:
None
See Also:
None
Example:
saveSR=OSSetSR(0x700); /* disable interrupts */
. /* do some stuff */
.
.
OSSetSR(saveSR); /* restore interrupts */

Texas Instruments TI-89 Specifications

General

Display size (HxV)	100 x 160 mm
Memory type	639K FLASH ROM, 188K bytes RAM
Compatible operating systems	Operating System 2.09
Battery type	AAA