Xilinx MicroBlaze Reference Manual page 19

Table 2-6: MicroBlaze Instruction Set Summary (Cont'd)
Type A
Type B
SBEA Rd,Ra,Rb 110100
SH Rd,Ra,Rb 110101
SHR Rd,Ra,Rb
SHEA Rd,Ra,Rb 110101
SW Rd,Ra,Rb 110110
SWR Rd,Ra,Rb
SWX Rd,Ra,Rb 110110
SWEA Rd,Ra,Rb 110110
LBUI Rd,Ra,Imm 111000
LHUI Rd,Ra,Imm 111001
LWI Rd,Ra,Imm 111010
SBI Rd,Ra,Imm 111100
SHI Rd,Ra,Imm 111101
SWI Rd,Ra,Imm 111110
1. Due to the many different corner cases involved in floating point arithmetic, only the normal behavior is described. A full
description of the behavior can be found in
Semaphore Synchronization
The LWX and SWX. instructions are used to implement common semaphore operations,
including test and set, compare and swap, exchange memory, and fetch and add. They are
also used to implement spinlocks.
These instructions are typically used by system programs and are called by application
programs as needed. Generally, a program uses LWX to load a semaphore from memory,
causing the reservation to be set (the processor maintains the reservation internally). The
program can compute a result based on the semaphore value and conditionally store the
result back to the same memory location using the SWX instruction. The conditional store
MicroBlaze Processor Reference Guide
UG984 (v2016.2) June 8, 2016
UG984 (v2016.1) April 6, 2016
0-5 6-10 11-15 16-20
0-5 6-10 11-15
Rd Ra Rb
Rd Ra Rb
Rd Ra Rb
Rd Ra Rb
Rd Ra Rb
Rd Ra Rb
Rd Ra
Rd Ra
Rd Ra
Rd Ra
Rd Ra
Rd Ra
Chapter 5, "MicroBlaze Instruction Set Architecture."
www.xilinx.com
Chapter 2: MicroBlaze Architecture
21-31
16-31
00010000000 Addr := Ra & Rb
*Addr[0:8] := Rd[24:31]
00000000000 Addr := Ra + Rb
*Addr[0:16] := Rd[16:31]
01000000000
00010000000 Addr := Ra & Rb
*Addr[0:16] := Rd[16:31]
00000000000 Addr := Ra + Rb
01000000000 *Addr := Rd
10000000000 Addr := Ra + Rb
*Addr := Rd if Reservation = 1
Reservation := 0
00010000000 Addr := Ra & Rb
*Addr := Rd
Imm Addr := Ra + s(Imm)
Rd[0:23] := 0
Rd[24:31] := *Addr[0:7]
Imm Addr := Ra + s(Imm)
Rd[0:15] := 0
Rd[16:31] := *Addr[0:15]
Imm Addr := Ra + s(Imm)
Rd := *Addr
Imm Addr := Ra + s(Imm)
*Addr[0:7] := Rd[24:31]
Imm Addr := Ra + s(Imm)
*Addr[0:15] := Rd[16:31]
Imm Addr := Ra + s(Imm)
*Addr := Rd
Semantics
19
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