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author | chriseth <chris@ethereum.org> | 2018-05-15 02:43:16 +0800 |
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committer | GitHub <noreply@github.com> | 2018-05-15 02:43:16 +0800 |
commit | 8f17f7219aec4586961af41b9bdd1804b3d59aa5 (patch) | |
tree | 0f0b60fd5e6e1865a3ea23aabba085ea456b855c | |
parent | ab63ab1cbb2f3fe68d2db991710b53e2c8c25f2d (diff) | |
parent | f753dda337a669c9e072ea4874de3caf05cae1ab (diff) | |
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Merge pull request #3238 from ethereum/julia-specs
Add logic builtins to Julia and update type conversion prototypes
-rw-r--r-- | docs/julia.rst | 52 |
1 files changed, 36 insertions, 16 deletions
diff --git a/docs/julia.rst b/docs/julia.rst index 078bc55b..bc918117 100644 --- a/docs/julia.rst +++ b/docs/julia.rst @@ -306,12 +306,20 @@ Type Conversion Functions JULIA has no support for implicit type conversion and therefore functions exists to provide explicit conversion. When converting a larger type to a shorter type a runtime exception can occur in case of an overflow. -The following type conversion functions must be available: -- ``u32tobool(x:u32) -> y:bool`` -- ``booltou32(x:bool) -> y:u32`` -- ``u32tou64(x:u32) -> y:u64`` -- ``u64tou32(x:u64) -> y:u32`` -- etc. (TBD) +Truncating conversions are supported between the following types: + - ``bool`` + - ``u32`` + - ``u64`` + - ``u256`` + - ``s256`` + +For each of these a type conversion function exists having the prototype in the form of ``<input_type>to<output_type>(x:<input_type>) -> y:<output_type>``, +such as ``u32tobool(x:u32) -> y:bool``, ``u256tou32(x:u256) -> y:u32`` or ``s256tou256(x:s256) -> y:u256``. + +.. note:: + + ``u32tobool(x:u32) -> y:bool`` can be implemented as ``y := not(iszerou256(x))`` and + ``booltou32(x:bool) -> y:u32`` can be implemented as ``switch x case true:bool { y := 1:u32 } case false:bool { y := 0:u32 }`` Low-level Functions ------------------- @@ -319,6 +327,16 @@ Low-level Functions The following functions must be available: +---------------------------------------------------------------------------------------------------------------+ +| *Logic* | ++---------------------------------------------+-----------------------------------------------------------------+ +| not(x:bool) -> z:bool | logical not | ++---------------------------------------------+-----------------------------------------------------------------+ +| and(x:bool, y:bool) -> z:bool | logical and | ++---------------------------------------------+-----------------------------------------------------------------+ +| or(x:bool, y:bool) -> z:bool | logical or | ++---------------------------------------------+-----------------------------------------------------------------+ +| xor(x:bool, y:bool) -> z:bool | xor | ++---------------------------------------------+-----------------------------------------------------------------+ | *Arithmetics* | +---------------------------------------------+-----------------------------------------------------------------+ | addu256(x:u256, y:u256) -> z:u256 | x + y | @@ -343,15 +361,19 @@ The following functions must be available: +---------------------------------------------+-----------------------------------------------------------------+ | mulmodu256(x:u256, y:u256, m:u256) -> z:u256| (x * y) % m with arbitrary precision arithmetics | +---------------------------------------------+-----------------------------------------------------------------+ -| ltu256(x:u256, y:u256) -> z:bool | 1 if x < y, 0 otherwise | +| ltu256(x:u256, y:u256) -> z:bool | true if x < y, false otherwise | +---------------------------------------------+-----------------------------------------------------------------+ -| gtu256(x:u256, y:u256) -> z:bool | 1 if x > y, 0 otherwise | +| gtu256(x:u256, y:u256) -> z:bool | true if x > y, false otherwise | +---------------------------------------------+-----------------------------------------------------------------+ -| sltu256(x:s256, y:s256) -> z:bool | 1 if x < y, 0 otherwise, for signed numbers in two's complement | +| sltu256(x:s256, y:s256) -> z:bool | true if x < y, false otherwise | +| | (for signed numbers in two's complement) | +---------------------------------------------+-----------------------------------------------------------------+ -| sgtu256(x:s256, y:s256) -> z:bool | 1 if x > y, 0 otherwise, for signed numbers in two's complement | +| sgtu256(x:s256, y:s256) -> z:bool | true if x > y, false otherwise | +| | (for signed numbers in two's complement) | +---------------------------------------------+-----------------------------------------------------------------+ -| equ256(x:u256, y:u256) -> z:bool | 1 if x == y, 0 otherwise | +| equ256(x:u256, y:u256) -> z:bool | true if x == y, false otherwise | ++---------------------------------------------+-----------------------------------------------------------------+ +| iszerou256(x:u256) -> z:bool | true if x == 0, false otherwise | +---------------------------------------------+-----------------------------------------------------------------+ | notu256(x:u256) -> z:u256 | ~x, every bit of x is negated | +---------------------------------------------+-----------------------------------------------------------------+ @@ -405,10 +427,6 @@ The following functions must be available: | insize:u256, out:u256, | but also keep ``caller`` | | outsize:u256) -> r:u256 | and ``callvalue`` | +---------------------------------------------+-----------------------------------------------------------------+ -| stop() | stop execution, identical to return(0,0) | -| | Perhaps it would make sense retiring this as it equals to | -| | return(0,0). It can be an optimisation by the EVM backend. | -+---------------------------------------------+-----------------------------------------------------------------+ | abort() | abort (equals to invalid instruction on EVM) | +---------------------------------------------+-----------------------------------------------------------------+ | return(p:u256, s:u256) | end execution, return data mem[p..(p+s)) | @@ -473,6 +491,8 @@ The following functions must be available: +---------------------------------------------+-----------------------------------------------------------------+ | *Others* | +---------------------------------------------+-----------------------------------------------------------------+ +| discard(unused:bool) | discard value | ++---------------------------------------------+-----------------------------------------------------------------+ | discardu256(unused:u256) | discard value | +---------------------------------------------+-----------------------------------------------------------------+ | splitu256tou64(x:u256) -> (x1:u64, x2:u64, | split u256 to four u64's | @@ -481,7 +501,7 @@ The following functions must be available: | combineu64tou256(x1:u64, x2:u64, x3:u64, | combine four u64's into a single u256 | | x4:u64) -> (x:u256) | | +---------------------------------------------+-----------------------------------------------------------------+ -| sha3(p:u256, s:u256) -> v:u256 | keccak(mem[p...(p+s))) | +| keccak256(p:u256, s:u256) -> v:u256 | keccak(mem[p...(p+s))) | +---------------------------------------------+-----------------------------------------------------------------+ Backends |