Xilinx MicroBlaze - Page 245

MicroBlaze Processor Reference Guide 246
UG984 (v2018.2) June 21, 2018 www.xilinx.com
Chapter 5: MicroBlaze Instruction Set Architecture
Pseudocode
if EA = 1 then
Addr ← (rA) & (rB)
else
Addr
← (rA) + (rB)
if TLB_Miss(Addr) and MSR[VM] = 1 then
ESR[EC]
← 10010;ESR[S]← 0
MSR[UMS] ← MSR[UM]; MSR[VMS] ← MSR[VM]; MSR[UM] ← 0; MSR[VM] ← 0
else if Access_Protected(Addr) and MSR[UM] = 1 and MSR[VM] = 1 then
ESR[EC]
← 10000;ESR[S]← 0; ESR[DIZ] ← 1
MSR[UMS] ← MSR[UM]; MSR[VMS] ← MSR[VM]; MSR[UM] ← 0; MSR[VM] ← 0
else if Addr[31] ≠ 0 then
ESR[EC]
← 00001; ESR[W] ← 0; ESR[S] ← 0; ESR[Rx] ← rD
else if (VM = 0 and R = 1) or
(VM = 1 and R = 1 and E = 1) or
(VM = 1 and R = 0 and E = 0) then
(rD)[16:23]
← Mem(Addr); (rD)[24:31] ← Mem(Addr+1); (rD)[0:15] ← 0
else
(rD)[16:23]
← Mem(Addr+1); (rD)[24:31] ← Mem(Addr); (rD)[0:15] ← 0
Registers Altered
• rD, unless an exception is generated, in which case the register is unchanged
• MSR[UM], MSR[VM], MSR[UMS], MSR[VMS], if an exception is generated
• ESR[EC], ESR[S], if an exception is generated
• ESR[DIZ], if a data storage exception is generated
• ESR[W], ESR[Rx], if an unaligned data access exception is generated
Latency
• 1 cycle with C_AREA_OPTIMIZED=0 or 2
• 2 cycles with
C_AREA_OPTIMIZED=1
Notes
The halfword reversed instruction is only valid if MicroBlaze is configured to use reorder instructions
(C_USE_REORDER_INSTR = 1).
The extended address instruction is only valid if MicroBlaze is configured to use extended address
(C_ADDR_SIZE > 32).
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