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| author | dos-reis <gdr@axiomatics.org> | 2013-05-26 08:26:06 +0000 |
|---|---|---|
| committer | dos-reis <gdr@axiomatics.org> | 2013-05-26 08:26:06 +0000 |
| commit | 3d124313d289fd42013e52f600283c99f8d0211a (patch) | |
| tree | 247fcfab11b70dfa40b711b1653d539673577f3e /src/algebra | |
| parent | cbd17230112800448956940165f541d7c49d0dc5 (diff) | |
| download | open-axiom-3d124313d289fd42013e52f600283c99f8d0211a.tar.gz | |
Define lexicographical ordering on Bits in Spad
Diffstat (limited to 'src/algebra')
| -rw-r--r-- | src/algebra/boolean.spad.pamphlet | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/src/algebra/boolean.spad.pamphlet b/src/algebra/boolean.spad.pamphlet index de430f03..14abe29e 100644 --- a/src/algebra/boolean.spad.pamphlet +++ b/src/algebra/boolean.spad.pamphlet @@ -137,7 +137,6 @@ IndexedBits(mn:Integer): BitAggregate() import %bitvecref: (%,Integer) -> NonNegativeInteger from Foreign Builtin import %bitveceq: (%,%) -> Boolean from Foreign Builtin - import %bitveclt: (%,%) -> Boolean from Foreign Builtin import %bitvecnot: % -> % from Foreign Builtin import %bitvecand: (%,%) -> % from Foreign Builtin import %bitvecor: (%,%) -> % from Foreign Builtin @@ -165,7 +164,15 @@ IndexedBits(mn:Integer): BitAggregate() copy v == %bitveccopy v #v == %bitveclength v v = u == %bitveceq(v,u) - v < u == %bitveclt(v,u) + u < v == -- lexicographic + nu := #u + nv := #v + for i in 0.. repeat + i >= nu => return or/[%bitvecref(v,j) = 1 for j in i..nv-1] + i >= nv => return false + %bitvecref(u,i) < %bitvecref(v,i) => return true + %bitvecref(u,i) > %bitvecref(v,i) => return false + u and v == (#v=#u => %bitvecand(v,u); map("and",v,u)) u or v == (#v=#u => %bitvecor(v,u); map("or", v,u)) xor(v,u) == (#v=#u => %bitvecxor(v,u); map("xor",v,u)) |