MicroBlaze Processor Reference Guide www.xilinx.com 115
UG081 (v6.0) June 1, 2006 1-800-255-7778
Move From Special Purpose Register
Copies the contents of the special purpose register rS into register rD.
case 0x0000 :
(rD) ← PC
case 0x0001 :
(rD) ← MSR
case 0x0003 :
(rD) ← EAR
case 0x0005 :
(rD) ← ESR
case 0x0007 :
(rD) ← FSR
case 0x000B :
(rD) ← BTR
case 0x200x :
(rD) ← PVR[x] (where x = 0 to 11)
(rD) ← Undefined
To refer to special purpose registers in assembly language, use rpc for PC, rmsr for MSR,
rear for EAR, resr for ESR, and rfsr for FSR.
Thevalue readfromMSRmay notincludeeffectsoftheimmediatelyprecedinginstruction
(dependent on pipeline stall behavior). A NOP should be inserted before the MFS
instruction to guarantee correct MSR value.
EAR and ESR are only valid as operands when at least one of the MicroBlaze
C_*_EXCEPTION parameters are set to 1.
FSR is only valid as an operand when the C_USE_FPU and C_FPU_EXCEPTION
parameters are set to 1.
mfs rD, rS
1 0 0 1 0 1 rD 0 0 0 0 0 1 0 rS
0 6 11 16 18 31