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Multi-row mvout reads incorrect scratchpad rows and corrupts output data #408
Description
Environment
- Gemmini:
8c3f9923 - Chipyard:
157dd69e - Verilator:
GemminiRocketConfig
Steps to reproduce
- Initialize two consecutive scratchpad rows with different values (
0xA3and0x5C, 16 bytes each). - Set the store stride to 16 bytes.
- Compare single-row and two-row
mvoutoperations:
gemmini_config_st(16);
// Single-row control
gemmini_extended_mvout(out1, 0, 16, 1);
gemmini_fence();
// Two-row test
gemmini_extended_mvout(out2, 0, 16, 2);
gemmini_fence();The scratchpad rows are initialized and verified before these operations.
Expected behavior
Both rows are transferred correctly to DRAM (A3×16, 5C×16).
Actual behavior
- Single-row
mvoutworks correctly. - Two-row
mvoutproduces corrupted data. - RTL traces indicate incorrect scratchpad row selection in the multi-row StoreController path, with pre-existing scratchpad contents appearing in the output.
The issue has been reproduced in multiple RTL simulations.
Activity