Missing ACT coverpoints

[jordancarlin]

The following instructions have coverage holes when run against the riscv-arch-test coverpoints. The general type of hole is listed for all instructions and specific examples of coverpoints are given for some.

Uncovered ACT coverpoints

I Extension

• general R type
  • many corners - Full coverage of several instruction types with ACT coverage metrics #486
• general I type
  • many corners - Full coverage of several instruction types with ACT coverage metrics #486
• beq, bge, blt, bne
  • Directions
    • rs1_val < rs2_val and imm_val < 0 and imm_val & 0x03 == 0
    • rs1_val == rs2_val and imm_val < 0 and imm_val & 0x03 == 0
    • rs1_val == rs2_val and imm_val > 0 and imm_val & 0x03 == 0
    • rs1_val > rs2_val and imm_val < 0 and imm_val & 0x03 == 0
• bgeu, bltu
  • Extra unsigned corners - Full coverage of several instruction types with ACT coverage metrics #486
  • Directions
• jal
  • ±2^18
• slli, slliw, srai, sraiw, srli, srliw
  • signs
    • rs1_val < 0 and imm_val == 0: 0
    • rs1_val > 0 and imm_val == (xlen-1)
  • rs1=imm
• sltu, sltiu
  • Extra unsigned corners - Full coverage of several instruction types with ACT coverage metrics #486
• lb-align
  • ea_align == 1 and (imm_val % 4) == 2: 0
  • ea_align == 2 and (imm_val % 4) == 3: 0
  • ea_align == 3 and (imm_val % 4) == 2: 0
• lbu-align (RV64 hole only)
  • ea_align == 2 and (imm_val % 4) == 1: 0
• lhu-align (RV32 hole only)
  • ea_align == 2 and (imm_val % 4) == 2: 0
• sb-align, sh-align
  • All with ea-align ≠ 0

NOTE: ea_align = (rs1_val + imm_val) % 4

Zbb Extension

• orc.b
  • rs1_val
    • rs1_val == 0x102040801020408: 0
    • rs1_val == 0x204080102040801: 0
    • rs1_val == 0x408010204080102: 0
    • rs1_val == 0x801020408010204: 0

M Extension

• Fully covered with Full coverage of several instruction types with ACT coverage metrics #486

Zaamo Extension

• Fully covered with Full coverage of several instruction types with ACT coverage metrics #486

Zba Extension

• Fully covered with Full coverage of several instruction types with ACT coverage metrics #486

Additional extensions to follow

• Zbs
• Zbc
• Zca
• Zcb
• Zcf
• Zcd
• D
• F
• Zfh
• Zfa
• Zicboz
• E
• Zbkb
• Zbkx
• Zkne
• Zknd
• Zknh
• Zicond
• Zifencei
• priv (ecall, ebreak, misalign)

[jordancarlin]

Here is the (very rough) script I'm using to gather this data. It's still a fairly manual process and required the specific list of instructions to be tested to be listed out. It also needs the rvtest_end symbol to be inserted into the footer of each test.

#!/bin/bash

# General variables
XLEN=64
FLEN=64
EXTENSION=I

# ISACOV variables
directory=i
coverage_file=rv"$XLEN"i.cgf
instruction=srli

# Run Sail to generate a trace file
riscv_sim_rv"$XLEN"d -i -v --trace=step --pmp-count=16 --pmp-grain=0 \
"$CVW_ARCH_VERIF"/tests/lockstep/rv$XLEN/$EXTENSION/WALLY-COV-"$instruction".elf > $EXTENSION.trace

# Run ISAC to generate a coverage report
riscv_isac coverage -d -t $EXTENSION.trace \
--parser-name c_sail --decoder-name internaldecoder -o $EXTENSION.rpt \
--sig-label begin_signature end_signature \
--test-label rvtest_entry_point rvtest_end  \
-e "$CVW_ARCH_VERIF"/tests/lockstep/rv$XLEN/$EXTENSION/WALLY-COV-"$instruction".elf \
-c "$WALLY"/addins/riscv-arch-test/coverage/dataset.cgf \
-c "$WALLY"/addins/riscv-arch-test/coverage/$directory/$coverage_file \
-x $XLEN -f $FLEN \
-l "$instruction"

# -l add -l addi -l addiw -l addw -l and -l andi -l auipc -l beq -l bge -l bgeu -l blt -l bltu -l bne -l jal \
# -l jalr -l lui -l or -l ori -l sll -l slli -l slliw -l sllw \
# -l slt -l slti -l sltiu -l sltu -l sra -l srai -l sraiw -l sraw -l srl -l srli -l srliw -l srlw -l sub -l subw \
# -l xor -l xori -l fence 
# -l lb-align -l lbu-align -l lh-align -l lhu-align -l lw-align -l lwu-align -l ld-align -l sb-align -l sh-align -l sw-align -l sd-align