Binary coded decimal: Difference between revisions
Created Nim solution.
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(Created Nim solution.) |
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BCD 30 (UInt8[0x30]) - BCD 1 ((UInt8[0x01], 1)[1]) = BCD 29 ((UInt8[0x29], 1))
BCD 99 (UInt8[0x99]) + BCD 1 ((UInt8[0x01], 1)[1]) = BCD 100 ((UInt8[0x01, 0x00], 1))
</pre>
=={{header|Nim}}==
{{trans|Rust}}
We define a type <code>Bcd64</code> as derived but distinct of <code>uint64</code> and operators and functions working on this type.
<syntaxhighlight lang="Nim">import std/strutils
type Bcd64 = distinct uint64
func `+`(a, b: Bcd64): Bcd64 =
let t1 = a.uint64 + 0x0666_6666_6666_6666u64
let t2 = t1 + b.uint64
let t3 = t1 xor b.uint64
let t4 = not(t2 xor t3) and 0x1111_1111_1111_1110u64
let t5 = (t4 shr 2) or (t4 shr 3)
result = Bcd64(t2 - t5)
func `-`(a: Bcd64): Bcd64 =
## Return 10's complement.
let t1 = cast[uint64](-cast[int64](a))
let t2 = t1 + 0xFFFF_FFFF_FFFF_FFFFu64
let t3 = t2 xor 1
let t4 = not(t2 xor t3) and 0x1111_1111_1111_1110u64
let t5 = (t4 shr 2) or (t4 shr 3)
result = Bcd64(t1 - t5)
func `-`(a, b: Bcd64): Bcd64 =
a + (-b)
func `$`(n: Bcd64): string =
var s = n.uint64.toHex
var i = 0
while i < s.len - 1 and s[i] == '0':
inc i
result = "0x" & s[i..^1]
const One = Bcd64(0x01u64)
echo "$1 + $2 = $3".format(Bcd64(0x19), One, Bcd64(0x19) + One)
echo "$1 - $2 = $3".format(Bcd64(0x30), One, Bcd64(0x30) - One)
echo "$1 + $2 = $3".format(Bcd64(0x99), One, Bcd64(0x99) + One)
</syntaxhighlight>
{{out}}
<pre>0x19 + 0x1 = 0x20
0x30 - 0x1 = 0x29
0x99 + 0x1 = 0x100
</pre>
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