From 6fc67c1fbc84ff24a43469946f672285a2796dc2 Mon Sep 17 00:00:00 2001
From: Michael McLoughlin <mmcloughlin@gmail.com>
Date: Thu, 27 Dec 2018 15:44:52 -0800
Subject: [PATCH] examples/geohash: first version

Adds helper for constants as DATA sections.
---
 build/global.go                  |  2 ++
 build/pseudo.go                  |  7 ++++++
 examples/geohash/asm.go          | 40 ++++++++++++++++++++++++++++++++
 examples/geohash/geohash.s       | 34 +++++++++++++++++++++++++++
 examples/geohash/geohash_test.go | 13 +++++++++++
 examples/geohash/stub.go         |  5 ++++
 6 files changed, 101 insertions(+)
 create mode 100644 examples/geohash/asm.go
 create mode 100644 examples/geohash/geohash.s
 create mode 100644 examples/geohash/geohash_test.go
 create mode 100644 examples/geohash/stub.go

diff --git a/build/global.go b/build/global.go
index b4eba59..0c3fdbc 100644
--- a/build/global.go
+++ b/build/global.go
@@ -58,3 +58,5 @@ func Load(src gotypes.Component, dst reg.Register) reg.Register { return ctx.Loa
 func Store(src reg.Register, dst gotypes.Component)             { ctx.Store(src, dst) }
 
 func AllocLocal(size int) operand.Mem { return ctx.AllocLocal(size) }
+
+func ConstData(name string, v operand.Constant) operand.Mem { return ctx.ConstData(name, v) }
diff --git a/build/pseudo.go b/build/pseudo.go
index d5ed6e7..f394c40 100644
--- a/build/pseudo.go
+++ b/build/pseudo.go
@@ -1,6 +1,7 @@
 package build
 
 import (
+	"github.com/mmcloughlin/avo/operand"
 	"github.com/mmcloughlin/avo/reg"
 
 	"github.com/mmcloughlin/avo/gotypes"
@@ -42,3 +43,9 @@ func (c *Context) Store(src reg.Register, dst gotypes.Component) {
 	}
 	c.mov(src, b.Addr, int(src.Bytes()), int(gotypes.Sizes.Sizeof(b.Type)), b.Type)
 }
+
+func (c *Context) ConstData(name string, v operand.Constant) operand.Mem {
+	g := c.StaticGlobal(name)
+	c.AppendDatum(v)
+	return g
+}
diff --git a/examples/geohash/asm.go b/examples/geohash/asm.go
new file mode 100644
index 0000000..213baad
--- /dev/null
+++ b/examples/geohash/asm.go
@@ -0,0 +1,40 @@
+// +build ignore
+
+package main
+
+import (
+	. "github.com/mmcloughlin/avo/build"
+	. "github.com/mmcloughlin/avo/operand"
+)
+
+func main() {
+	TEXT("EncodeInt", "func(lat, lng float64) uint64")
+	lat := Load(Param("lat"), Xv())
+	lng := Load(Param("lng"), Xv())
+
+	MULSD(ConstData("reciprocal180", F64(1/180.0)), lat)
+	onepointfive := ConstData("onepointfive", F64(1.5))
+	ADDSD(onepointfive, lat)
+
+	MULSD(ConstData("reciprocal360", F64(1/360.0)), lng)
+	ADDSD(onepointfive, lng)
+
+	lngi, lati := GP64v(), GP64v()
+	MOVQ(lat, lati)
+	SHRQ(U8(20), lati)
+	MOVQ(lng, lngi)
+	SHRQ(U8(20), lngi)
+
+	mask := ConstData("mask", U64(0x5555555555555555))
+	ghsh := GP64v()
+	PDEPQ(mask, lati, ghsh)
+	temp := GP64v()
+	PDEPQ(mask, lngi, temp)
+	SHLQ(U8(1), temp)
+	XORQ(temp, ghsh)
+
+	Store(ghsh, ReturnIndex(0))
+	RET()
+
+	Generate()
+}
diff --git a/examples/geohash/geohash.s b/examples/geohash/geohash.s
new file mode 100644
index 0000000..4cde229
--- /dev/null
+++ b/examples/geohash/geohash.s
@@ -0,0 +1,34 @@
+// Code generated by command: go run asm.go -out geohash.s -stubs stub.go. DO NOT EDIT.
+
+#include "textflag.h"
+
+// func EncodeInt(lat float64, lng float64) uint64
+TEXT ·EncodeInt(SB), 0, $0-24
+	MOVSD	lat(FP), X0
+	MOVSD	lng+8(FP), X1
+	MULSD	reciprocal180<>(SB), X0
+	ADDSD	onepointfive<>(SB), X0
+	MULSD	reciprocal360<>(SB), X1
+	ADDSD	onepointfive<>(SB), X1
+	MOVQ	X0, CX
+	SHRQ	$0x14, CX
+	MOVQ	X1, AX
+	SHRQ	$0x14, AX
+	PDEPQ	mask<>(SB), CX, CX
+	PDEPQ	mask<>(SB), AX, AX
+	SHLQ	$0x01, AX
+	XORQ	AX, CX
+	MOVQ	CX, ret+16(FP)
+	RET
+
+DATA reciprocal180<>(SB)/8, $(0.005555555555555556)
+GLOBL reciprocal180<>(SB), RODATA, $8
+
+DATA onepointfive<>(SB)/8, $(1.5)
+GLOBL onepointfive<>(SB), RODATA, $8
+
+DATA reciprocal360<>(SB)/8, $(0.002777777777777778)
+GLOBL reciprocal360<>(SB), RODATA, $8
+
+DATA mask<>(SB)/8, $0x5555555555555555
+GLOBL mask<>(SB), RODATA, $8
diff --git a/examples/geohash/geohash_test.go b/examples/geohash/geohash_test.go
new file mode 100644
index 0000000..6605ada
--- /dev/null
+++ b/examples/geohash/geohash_test.go
@@ -0,0 +1,13 @@
+package geohash
+
+import (
+	"testing"
+)
+
+//go:generate go run asm.go -out geohash.s -stubs stub.go
+
+func TestEncodeIntMountEverest(t *testing.T) {
+	if EncodeInt(27.988056, 86.925278) != 0xceb7f254240fd612 {
+		t.Fail()
+	}
+}
diff --git a/examples/geohash/stub.go b/examples/geohash/stub.go
new file mode 100644
index 0000000..65ab94f
--- /dev/null
+++ b/examples/geohash/stub.go
@@ -0,0 +1,5 @@
+// Code generated by command: go run asm.go -out geohash.s -stubs stub.go. DO NOT EDIT.
+
+package geohash
+
+func EncodeInt(lat float64, lng float64) uint64