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Add support for unsigned decimals #265

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b9edb02
Add support for unsigned decimals
pjuftring Mar 21, 2016
6e00599
Add overflow-check and allow '+'
pjuftring Mar 22, 2016
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30 changes: 29 additions & 1 deletion ml-proto/spec/int.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -208,7 +208,35 @@ struct
let ge_s x y = x >= y
let ge_u x y = cmp_u x (>=) y

let of_string = Rep.of_string
(* to_string supports unsigned decimals *)
let of_string x =
let unsigned_decimal x =
let ten = Rep.of_int 10 in
let l = String.length x in
(* First overflow-check via String.length *)
if l > (if Rep.bitwidth = 32 then 10 else 20)
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Hm, this effectively hard-codes that we only instantiate with 32 and 64 bit. It would be more modular to have a generic criterium, e.g. bitwidth / 3.

then raise (Failure "int_to_string");
let firstPart = Rep.of_string (String.sub x 0 (l - 1)) in
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Style nit: Ocaml prefers snake_casing

let secondPart = Rep.of_string (String.sub x (l - 1) 1) in
(* Negativity-check *)
if firstPart < Rep.zero
then raise (Failure "int_to_string");
(* Second overflow-check *)
if firstPart > (div_u Rep.minus_one ten)
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Nit: redundant parens around the div_u (same below)

|| (firstPart = (div_u Rep.minus_one ten) && secondPart > (rem_u Rep.minus_one ten))
then raise (Failure "int_to_string");
Rep.add
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Nit: can we put this on one line? Also, you can shorten to Rep.(add (mul ...) ...)

(Rep.mul
firstPart
(Rep.of_int 10))
secondPart
in
let l = String.length x in
(* OCaml doesn't like '+' in front of numbers, while host/lexer.mll allows it *)
let number_sans_plus = if String.get x 0 = '+' then String.sub x 1 (l - 1) else x in
try Rep.of_string number_sans_plus with
Failure _ -> unsigned_decimal number_sans_plus;;

let to_string = Rep.to_string

let of_int = Rep.of_int
Expand Down
12 changes: 12 additions & 0 deletions ml-proto/test/int_literals.wast
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,8 @@
(func $i32.inc_smin (result i32) (return (i32.add (i32.const -0x80000000) (i32.const 1))))
(func $i32.neg_zero (result i32) (return (i32.const -0x0)))
(func $i32.not_octal (result i32) (return (i32.const 010)))
(func $i32.unsigned_decimal (result i32) (return (i32.const 4294967295)))
(func $i32.plus_sign (result i32) (return (i32.const +42)))

(func $i64.test (result i64) (return (i64.const 0x0CABBA6E0ba66a6e)))
(func $i64.umax (result i64) (return (i64.const 0xffffffffffffffff)))
Expand All @@ -18,6 +20,8 @@
(func $i64.inc_smin (result i64) (return (i64.add (i64.const -0x8000000000000000) (i64.const 1))))
(func $i64.neg_zero (result i64) (return (i64.const -0x0)))
(func $i64.not_octal (result i64) (return (i64.const 010)))
(func $i64.unsigned_decimal (result i64) (return (i64.const 18446744073709551615)))
(func $i64.plus_sign (result i64) (return (i64.const +42)))

(export "i32.test" $i32.test)
(export "i32.umax" $i32.umax)
Expand All @@ -28,6 +32,8 @@
(export "i32.inc_smin" $i32.inc_smin)
(export "i32.neg_zero" $i32.neg_zero)
(export "i32.not_octal" $i32.not_octal)
(export "i32.unsigned_decimal" $i32.unsigned_decimal)
(export "i32.plus_sign" $i32.plus_sign)

(export "i64.test" $i64.test)
(export "i64.umax" $i64.umax)
Expand All @@ -38,6 +44,8 @@
(export "i64.inc_smin" $i64.inc_smin)
(export "i64.neg_zero" $i64.neg_zero)
(export "i64.not_octal" $i64.not_octal)
(export "i64.unsigned_decimal" $i64.unsigned_decimal)
(export "i64.plus_sign" $i64.plus_sign)
)

(assert_return (invoke "i32.test") (i32.const 195940365))
Expand All @@ -49,6 +57,8 @@
(assert_return (invoke "i32.inc_smin") (i32.const -2147483647))
(assert_return (invoke "i32.neg_zero") (i32.const 0))
(assert_return (invoke "i32.not_octal") (i32.const 10))
(assert_return (invoke "i32.unsigned_decimal") (i32.const -1))
(assert_return (invoke "i32.plus_sign") (i32.const 42))

(assert_return (invoke "i64.test") (i64.const 913028331277281902))
(assert_return (invoke "i64.umax") (i64.const -1))
Expand All @@ -59,3 +69,5 @@
(assert_return (invoke "i64.inc_smin") (i64.const -9223372036854775807))
(assert_return (invoke "i64.neg_zero") (i64.const 0))
(assert_return (invoke "i64.not_octal") (i64.const 10))
(assert_return (invoke "i64.unsigned_decimal") (i64.const -1))
(assert_return (invoke "i64.plus_sign") (i64.const 42))