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Proof step 18 from proof crash-neutral-write-data-wl (previous step)

apebs[n2] = mkpeb(aehdr, avhdr, buf0, 0, false), n1 = align↑(datasize(buf, n1), EB_PAGE_SIZE), avhdr.valid?, aehdr.valid?, n2 < # apebs, ubi-io-inv(apebs), n1 ≤ # buf, n1 ≤ LEB_SIZE ⊦ # mkbuf(0) ≤ n1 ∧ is-aligned(# mkbuf(0), EB_PAGE_SIZE) ∧ ( datasize(mkbuf(0), # mkbuf(0)) < datasize(buf, n1) ∨ checksum(mkbuf(0) + mkempbuf(n1 - # mkbuf(0)), datasize(buf, n1)) ≠ checksum(buf, datasize(buf, n1))) ∧ ⟨apebs1 := apebs[n2, mkpeb(apebs[n2].echdr, apebs[n2].vidhdr, mkbuf(0) + mkempbuf(LEB_SIZE - # mkbuf(0)), # mkbuf(0), apebs[n2].bad)]⟩ (apebs = apebs1), datasize(buf, n1) = 0

Heuristic simplifier applied rule simplifier

And obtained the following new goals

Proof step 19:
apebs[n2] = mkpeb(aehdr, avhdr, buf0, 0, false), n1 = align↑(datasize(buf, n1), EB_PAGE_SIZE), datasize(buf, n1) ≠ 0, aehdr.valid?, avhdr.valid?, n2 < # apebs, ubi-io-inv(apebs), n1 ≤ LEB_SIZE, n1 ≤ # buf ⊦ ⟨apebs1 := apebs[n2, mkpeb(apebs[n2].echdr, apebs[n2].vidhdr, mkempbuf(LEB_SIZE - 0), 0, apebs[n2].bad)]⟩ (apebs = apebs1)

Rule argument

Additional information

Used simplifier rules: append-a: ⊦ (buf + buf0) + buf1 = buf + buf0 + buf1; from specification array-splice[buffer]% ⊦ mkbuf(0) + buf = buf; (s)% ⊦ 0 < m ↔ m ≠ 0; (s)% ⊦ datasize(buf, 0) = 0; (s)%n ≠ 0 ⊦ is-aligned(0, n); (s)% ⊦ EB_PAGE_SIZE ≠ 0; (s)% ⊦ 0 ≤ m; (s)% ⊦ # mkbuf(n) = n; (s)