XC2200 Derivatives
System Units (Vol. 1 of 2)
Central Processing Unit (CPU)
User’s Manual
4-28
V2.1, 2008-08
CPUSV2_X, V2.2
Example for dedicated stall debug instructions:
STALLAM da,ha,dm,hm ;Opcode: 44 dahadmhm
STALLEW de,he,dw,hw ;Opcode: 45 dehedwhw
;Stalls the corresponding pipeline
;stage after “d” cycles for “h” cycles
;(“d” and “h” are 6-bit values)
Note: In general, these registers must not be modified by application software
(exceptions will be documented, e.g. in an errata sheet).
OVRUN
4
rw
Pipeline Control
0
Overrun of pipeline bubbles not allowed
1
Overrun of pipeline bubbles allowed
RETST
3
rw
Enable Return Stack
0
Return Stack is disabled
1
Return Stack is enabled
DAID
1
rw
Disable Atomic Injection Deny
0
Injection-requests are denied during Atomic
1
Injection-requests are not denied during
Atomic
SL
0
rw
Enables Short Loop Mode
0
Short loop mode disabled
1
Short loop mode enabled
Field
Bits
Type
Description