Texas Instruments TMS320C67X/C67X+ DSP - Manual (Page 407)

Globally Enabling and Disabling Interrupts
Interrupts 5-12 SPRU733
Example 5−2. Code Sequence to Disable Maskable Interrupts Globally
MVC CSR,B0 ; get CSR
AND -2,B0,B0 ; get ready to clear GIE
MVC B0,CSR ; clear GIE
Example 5−3. Code Sequence to Enable Maskable Interrupts Globally
MVC CSR,B0 ; get CSR
OR 1,B0,B0 ; get ready to set GIE
MVC B0,CSR ; set GIE