Machine Stream Register (mstream) - 2025.1 English - UG1629

MicroBlaze V Processor Reference Guide (UG1629)

Document ID
UG1629
Release Date
2025-07-09
Version
2025.1 English

The mstream register is a read/write custom CSR with the number 0x7C0. It holds information related to executed AXI4-Stream custom instructions. It only exists when AXI4-Stream custom instructions are enabled (C_FSL_LINKS > 0).

Figure 1. Machine Stream Register

Table 1. Machine Stream Register
Bits Name Description Reset Value
1 FSL

GET or GETD custom instruction TLAST control bit mismatch.

A mismatch occurs when the custom instruction expects TLAST to be set (the instruction 'c' bit is set) and it is not, or vice versa.

This bit is sticky, meaning that it is set by the first GET or GETD custom instruction with a mismatch, and remains set until cleared by software.

0
0 C A non-blocking GET or GETD custom instruction sets this bit to 1 if no data is available and to 0 if valid data is read.

A non-blocking PUT or PUTD custom instruction sets this bit to 1 if data could not be written and to 0 if data is successfully written.

This bit represents the result of the last executed non-blocking custom instruction.

0