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F multiply accumulate instructions set underflow flag of fflags wrongly #726

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salaheddinhetalani opened this issue Sep 27, 2022 · 1 comment
Closed

F multiply accumulate instructions set underflow flag of fflags wrongly #726

salaheddinhetalani opened this issue Sep 27, 2022 · 1 comment
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Component:RTL For issues in the RTL (e.g. for files in the rtl directory) PARAM:FPU Issue depends on the FPU parameter Status:Resolved Issue has been resolved, but closure is pending on git merge and/or issuer confirmation Type:Bug For bugs in the RTL, Documentation, Verification environment or Tool and Build system

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@salaheddinhetalani
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Issue Description

FMADD.S, FMSUB.S, FNMADD.S, FNMSUB.S instructions set underflow flag "UF" of fflags wrongly.

Component

Component:RTL

RISC-V Specification

The Zfinx extension adds all of the instructions that the F extension adds, except for the transfer instructions FLW, FSW, FMV.W.X, FMV.X.W, C.FLW[SP], and C.FSW[SP].

The Zfinx variants of these F-extension instructions have the same semantics, except that whenever such an instruction would have accessed an f register, it instead accesses the x register with the same number.

Steps to Reproduce

As shown below, the following sequence of instructions happens:

fmadd.s x30, x1, x10, x23, RMM

The instruction fmadd.s is decoded at t##0 and executed updating the integer register file at t##1 while setting the underflow flag UF of fflags CSR wrongly.

Bug_9

Top Level Parameters

cv32e40p_wrapper #(
    .PULP_XPULP       (0),
    .PULP_CLUSTER     (0),
    .FPU              (1),
    .PULP_ZFINX       (1),
    .NUM_MHPMCOUNTERS (1)
)

Git Hash: d0d1c25
Flist: cv32e40p_fpu_manifest.flist
VCD: bug_9.vcd

Product: OneSpin 360 DV-Verify
App: Processor Verification App
Tool's version: 2022.3_1
@pascalgouedo pascalgouedo added Component:RTL For issues in the RTL (e.g. for files in the rtl directory) PARAM:FPU Issue depends on the FPU parameter labels Nov 9, 2022
@pascalgouedo pascalgouedo added the Type:Bug For bugs in the RTL, Documentation, Verification environment or Tool and Build system label Mar 23, 2023
This was referenced Aug 2, 2023
Closed
Merged
pascalgouedo pushed a commit to pascalgouedo/cv32e40p that referenced this issue Aug 16, 2023
Issues openhwgroup#726 and openhwgroup#729 correction.
6933aaf 
Signed-off-by: Pascal Gouedo <[email protected]>
pascalgouedo pushed a commit to pascalgouedo/cv32e40p that referenced this issue Aug 16, 2023
Issues openhwgroup#726 and openhwgroup#729 correction.
fcaaf84 
Signed-off-by: Pascal Gouedo <[email protected]>
@pascalgouedo pascalgouedo mentioned this issue Aug 21, 2023
Merged
pascalgouedo pushed a commit to pascalgouedo/cv32e40p that referenced this issue Aug 21, 2023
Issues openhwgroup#726 and openhwgroup#729 correction.
53ce0f8 
Signed-off-by: Pascal Gouedo <[email protected]>
pascalgouedo pushed a commit to pascalgouedo/cv32e40p that referenced this issue Aug 22, 2023
Issues openhwgroup#726 and openhwgroup#729 correction.
7db67d7 
Signed-off-by: Pascal Gouedo <[email protected]>
pascalgouedo pushed a commit to pascalgouedo/cv32e40p that referenced this issue Aug 29, 2023
Issues openhwgroup#726 and openhwgroup#729 correction.
072d191 
Signed-off-by: Pascal Gouedo <[email protected]>
@pascalgouedo pascalgouedo mentioned this issue Aug 30, 2023
Merged
pascalgouedo pushed a commit to pascalgouedo/cv32e40p that referenced this issue Aug 30, 2023
CVFPU 0.8.1 vendorized for bugs correction
f3a904f 
- Fix Underflow flag for MUL and DIV/SQRT operations (openhwgroup#94 openhwgroup#726 openhwgroup#729)
- Fix for Float to Int conversion (openhwgroup#97 openhwgroup#83 openhwgroup#727)
- Fixed unnecessary trailing semicolon (openhwgroup#99)

Signed-off-by: Pascal Gouedo <[email protected]>
@pascalgouedo pascalgouedo mentioned this issue Aug 30, 2023
Merged
@pascalgouedo
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Resolved with PR #860

@pascalgouedo pascalgouedo added the Status:Resolved Issue has been resolved, but closure is pending on git merge and/or issuer confirmation label Oct 26, 2023
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Labels
Component:RTL For issues in the RTL (e.g. for files in the rtl directory) PARAM:FPU Issue depends on the FPU parameter Status:Resolved Issue has been resolved, but closure is pending on git merge and/or issuer confirmation Type:Bug For bugs in the RTL, Documentation, Verification environment or Tool and Build system
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@salaheddinhetalani @pascalgouedo