doc: show more examples in README

This commit is contained in:
Michael McLoughlin
2019-01-03 22:20:25 -08:00
parent 91e048ff29
commit fa7b5ed1dd
2 changed files with 74 additions and 1 deletions

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@@ -88,6 +88,79 @@ func Add(x uint64, y uint64) uint64
See the [`examples/add`](examples/add) directory for the complete working example.
## Examples
### Slice Sum
Sum a slice of `uint64`s:
[embedmd]:# (examples/sum/asm.go /func main/ /^}/)
```go
func main() {
TEXT("Sum", "func(xs []uint64) uint64")
Doc("Sum returns the sum of the elements in xs.")
ptr := Load(Param("xs").Base(), GP64v())
n := Load(Param("xs").Len(), GP64v())
s := GP64v()
XORQ(s, s)
LABEL("loop")
CMPQ(n, operand.Imm(0))
JE(operand.LabelRef("done"))
ADDQ(operand.Mem{Base: ptr}, s)
ADDQ(operand.Imm(8), ptr)
DECQ(n)
JMP(operand.LabelRef("loop"))
LABEL("done")
Store(s, ReturnIndex(0))
RET()
Generate()
}
```
### Parameter Load/Store
`avo` provides deconstruction of complex data datatypes into components. For example, load the length of a string argument with:
[embedmd]:# (examples/args/asm.go go /.*TEXT.*StringLen/ /Load.*/)
```go
TEXT("StringLen", "func(s string) int")
strlen := Load(Param("s").Len(), GP64v())
```
Index an array:
[embedmd]:# (examples/args/asm.go go /.*TEXT.*ArrayThree/ /Load.*/)
```go
TEXT("ArrayThree", "func(a [7]uint64) uint64")
a3 := Load(Param("a").Index(3), GP64v())
```
Access a struct field (provided you have loaded your package with the `Package` function):
[embedmd]:# (examples/args/asm.go go /.*TEXT.*FieldFloat64/ /Load.*/)
```go
TEXT("FieldFloat64", "func(s Struct) float64")
f64 := Load(Param("s").Field("Float64"), Xv())
```
Component accesses can be arbitrarily nested:
[embedmd]:# (examples/args/asm.go go /.*TEXT.*FieldArrayTwoBTwo/ /Load.*/)
```go
TEXT("FieldArrayTwoBTwo", "func(s Struct) byte")
b2 := Load(Param("s").Field("Array").Index(2).Field("B").Index(2), GP8v())
```
Very similar techniques apply to writing return values. See [`examples/args`](examples/args) and [`examples/returns`](examples/returns) for the full suite of examples.
### Real Examples
* **[fnv1a](fnv1a):** [FNV-1a](https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function#FNV-1a_hash) hash function.
* **[dot](dot):** Vector dot product.
* **[geohash](geohash):** Integer [geohash](https://en.wikipedia.org/wiki/Geohash) encoding.
* **[sha1](sha1):** [SHA-1](https://en.wikipedia.org/wiki/SHA-1) cryptographic hash.
* **[stadtx](stadtx):** [`StadtX` hash](https://github.com/demerphq/BeagleHash) port from [dgryski/go-stadtx](https://github.com/dgryski/go-stadtx).
## Contributing
Contributions to `avo` are welcome:

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@@ -1,6 +1,6 @@
# sum
Sum an array of `uint64`s.
Sum a slice of `uint64`s.
[embedmd]:# (asm.go go /func main/ /^}/)
```go