diff --git a/hw/snitch_cluster/src/snitch_cluster_peripheral/snitch_cluster_peripheral_reg.hjson b/hw/snitch_cluster/src/snitch_cluster_peripheral/snitch_cluster_peripheral_reg.hjson index 729967c1c..e3a0c485c 100644 --- a/hw/snitch_cluster/src/snitch_cluster_peripheral/snitch_cluster_peripheral_reg.hjson +++ b/hw/snitch_cluster/src/snitch_cluster_peripheral/snitch_cluster_peripheral_reg.hjson @@ -39,7 +39,7 @@ desc: ''' Increased whenever the TCDM is accessed. Each individual access is tracked, so if `n` cores access the TCDM, `n` will be added. Accesses are tracked at the TCDM, - so it doesn't matter whether the cores or the for example the SSR hardware accesses + so it doesn't matter whether the cores or for example the SSR hardware accesses the TCDM. _This is a cluster-global signal._ ''' }, @@ -48,8 +48,8 @@ resval: "0", name: "TCDM_CONGESTED" desc: ''' - Incremented whenever an access twoards the TCDM is made but the arbitration - logic didn't grant the access (due to congestion). Is strictly less than TCDM_ACCESSED. + Incremented whenever an access towards the TCDM is made but the arbitration + logic didn't grant the access (due to congestion). It's strictly less than TCDM_ACCESSED. _This is a cluster-global signal._ ''' }, @@ -58,7 +58,10 @@ resval: "0", name: "ISSUE_FPU" desc: ''' - Core operations performed in the FPU. _This is a hart-local signal._ + Operations performed in the FPU. Includes both operations initiated by the + sequencer and by the core. When the Xfrep extension is available, this counter is + equivalent to ISSUE_FPU_SEQ (see description of ISSUE_FPU_SEQ). If the Xfrep extension + is not supported, then it is equivalent to ISSUE_CORE_TO_FPU. _This is a hart-local signal._ ''' }, { @@ -67,7 +70,11 @@ name: "ISSUE_FPU_SEQ" desc: ''' Incremented whenever the FPU Sequencer issues an FPU instruction. - Might be non available if the hardware doesn't support FREP. + Might not be available if the hardware doesn't support FREP. + Note that all FP instructions offloaded by the core to the FPU are routed + through the sequencer (although not necessarily buffered) and thus are also counted. + The instructions issued independently by the FPU sequencer could thus be + calculated as ISSUE_FPU_SEQ_PROPER = ISSUE_FPU_SEQ - ISSUE_CORE_TO_FPU. _This is a hart-local signal._ ''' }, @@ -83,7 +90,9 @@ resval: "0", name: "RETIRED_INSTR" desc: ''' - Instructions retired by the core. _This is a hart-local signal._ + Instructions retired by the core, both offloaded and not. Does not + count instructions issued independently by the FPU sequencer. + _This is a hart-local signal._ ''' }, {