all: rename __reg to __volatile

It is less magical now: it only marks loads and stores as volatile. So
the name '__reg' is a bit wrong now.

compiler.go

@@ -1559,7 +1559,7 @@ func (c *Compiler) parseInstr(frame *Frame, instr ssa.Instruction) error {
 		}
 		store := c.builder.CreateStore(llvmVal, llvmAddr)
 		valType := instr.Addr.Type().(*types.Pointer).Elem()
-		if valType, ok := valType.(*types.Named); ok && valType.Obj().Name() == "__reg" {
+		if valType, ok := valType.(*types.Named); ok && valType.Obj().Name() == "__volatile" {
 			// Magic type name to make this store volatile, for memory-mapped
 			// registers.
 			store.SetVolatile(true)
@@ -2982,7 +2982,7 @@ func (c *Compiler) parseUnOp(frame *Frame, unop *ssa.UnOp) (llvm.Value, error) {
 	case token.MUL: // *x, dereference pointer
 		valType := unop.X.Type().(*types.Pointer).Elem()
 		load := c.builder.CreateLoad(x, "")
-		if valType, ok := valType.(*types.Named); ok && valType.Obj().Name() == "__reg" {
+		if valType, ok := valType.(*types.Named); ok && valType.Obj().Name() == "__volatile" {
 			// Magic type name to make this load volatile, for memory-mapped
 			// registers.
 			load.SetVolatile(true)

gen-device-avr.py

@@ -143,10 +143,10 @@ package {pkgName}
 import "unsafe"
 
 // Magic type name for the compiler.
-type __reg uint8
+type __volatile uint8
 
 // Export this magic type name.
-type RegValue = __reg
+type RegValue = __volatile
 
 // Some information about this device.
 const (
@@ -169,7 +169,7 @@ const (
         out.write('\n\t// {description}\n'.format(**peripheral))
         for register in peripheral['registers']:
             for variant in register['variants']:
-                out.write('\t{name} = (*__reg)(unsafe.Pointer(uintptr(0x{address:x})))\n'.format(**variant))
+                out.write('\t{name} = (*__volatile)(unsafe.Pointer(uintptr(0x{address:x})))\n'.format(**variant))
     out.write(')\n')
 
     for peripheral in device.peripherals:

gen-device-svd.py

@@ -158,10 +158,10 @@ package {pkgName}
 import "unsafe"
 
 // Magic type name for the compiler.
-type __reg uint32
+type __volatile uint32
 
 // Export this magic type name.
-type RegValue = __reg
+type RegValue = __volatile
 
 // Some information about this device.
 const (
@@ -193,14 +193,14 @@ const (
             if address < register['address']:
                 numSkip = (register['address'] - address) // 4
                 if numSkip == 1:
-                    out.write('\t_padding{padNumber} __reg\n'.format(padNumber=padNumber))
+                    out.write('\t_padding{padNumber} __volatile\n'.format(padNumber=padNumber))
                 else:
-                    out.write('\t_padding{padNumber} [{num}]__reg\n'.format(padNumber=padNumber, num=numSkip))
+                    out.write('\t_padding{padNumber} [{num}]__volatile\n'.format(padNumber=padNumber, num=numSkip))
                 padNumber += 1
 
-            regType = '__reg'
+            regType = '__volatile'
             if register['array'] is not None:
-                regType = '[{}]__reg'.format(register['array'])
+                regType = '[{}]__volatile'.format(register['array'])
             out.write('\t{name} {regType}\n'.format(**register, regType=regType))
 
             # next address

src/device/arm/arm.go

@@ -33,8 +33,8 @@ import (
 	"unsafe"
 )
 
-type __reg uint32
-type RegValue = __reg
+type __volatile uint32
+type RegValue = __volatile
 
 type __asm string
 
@@ -47,7 +47,7 @@ const (
 
 // Nested Vectored Interrupt Controller (NVIC).
 type NVIC_Type struct {
-	ISER [8]__reg
+	ISER [8]__volatile
 }
 
 var NVIC = (*NVIC_Type)(unsafe.Pointer(uintptr(NVIC_BASE)))