Implemented new functions to format literals as seperated hex tokens

The two main reasons behind this change are ensuring that the numbers
(mostly addresses, masks and default values) line up with the datasheet
for easier searching and verification since those are pretty much always
expressed in hexadecimal. The other reason being clippy now complains
about long numeric literals (without seperators) being hard to read -- I
agree.

Signed-off-by: Daniel Egger <daniel@eggers-club.de>

Author: Daniel Egger

src/generate.rs

@@ -5,7 +5,7 @@ use cast::u64;
 use quote::{Tokens, ToTokens};
 use svd::{Access, BitRange, Defaults, Device, EnumeratedValues, Field,
           Peripheral, Register, Usage, WriteConstraint};
-use syn::{self, Ident, Lit};
+use syn::{self, Ident};
 
 use errors::*;
 use util::{self, ToSanitizedSnakeCase, ToSanitizedUpperCase, U32Ext, BITS_PER_BYTE};
@@ -424,7 +424,7 @@ pub fn peripheral(
 ) -> Result<()> {
     let name = Ident::new(&*p.name.to_uppercase());
     let name_pc = Ident::new(&*p.name.to_sanitized_upper_case());
-    let address = util::unsuffixed(u64(p.base_address));
+    let address = util::hex(p.base_address);
     let description = util::respace(p.description.as_ref().unwrap_or(&p.name));
 
     items.push(quote! {
@@ -756,7 +756,7 @@ pub fn register(
         let rv = register
             .reset_value
             .or(defs.reset_value)
-            .map(|rv| util::unsuffixed(u64(rv)))
+            .map(|rv| util::hex(rv))
             .ok_or_else(|| {
                 format!("Register {} has no reset value",
                                     register.name)
@@ -868,9 +868,9 @@ pub fn fields(
         access: Option<Access>,
         description: String,
         evs: &'a [EnumeratedValues],
-        mask: Lit,
+        mask: Tokens,
         name: &'a str,
-        offset: Lit,
+        offset: Tokens,
         pc_r: Ident,
         pc_w: Ident,
         sc: Ident,
@@ -914,9 +914,9 @@ pub fn fields(
                 access: f.access,
                 evs: &f.enumerated_values,
                 sc: Ident::new(&*sc),
-                mask: util::unsuffixed_or_bool((1 << width) - 1, width),
+                mask: util::hex_or_bool((((1 as u64) << width) - 1) as u32, width),
                 name: &f.name,
-                offset: util::unsuffixed(u64(f.bit_range.offset)),
+                offset: util::hex(f.bit_range.offset),
                 ty: width.to_ty()?,
                 write_constraint: f.write_constraint.as_ref(),
             })
@@ -1077,7 +1077,7 @@ pub fn fields(
                         .iter()
                         .map(|v| {
                             let value =
-                                util::unsuffixed_or_bool(v.value, f.width);
+                                util::hex_or_bool(v.value as u32, f.width);
                             let pc = &v.pc;
 
                             quote! {

src/util.rs

@@ -4,6 +4,7 @@ use inflections::Inflect;
 use svd::{self, Access, EnumeratedValues, Field, Peripheral, Register,
           Usage};
 use syn::{self, Ident, IntTy, Lit};
+use quote::Tokens;
 
 use errors::*;
 
@@ -279,6 +280,32 @@ pub fn access_of(register: &Register) -> Access {
         )
 }
 
+/// Turns `n` into an unsuffixed separated hex tokens
+pub fn hex(n: u32) -> Tokens {
+    let mut t = Tokens::new();
+    let (h2, h1) = ((n >> 16) & 0xffff, n & 0xffff);
+    t.append(if h2 != 0 {
+        format!("0x{:04x}_{:04x}", h2, h1)
+    } else if h1 & 0xff00 != 0 {
+        format!("0x{:04x}", h1)
+    } else if h1 != 0 {
+        format!("0x{:02x}", h1 & 0xff)
+    } else {
+        String::from("0")
+    });
+    t
+}
+
+pub fn hex_or_bool(n: u32, width: u32) -> Tokens {
+    if width == 1 {
+        let mut t = Tokens::new();
+        t.append(if n == 0 { "false" } else { "true" });
+        t
+    } else {
+        hex(n)
+    }
+}
+
 /// Turns `n` into an unsuffixed literal
 pub fn unsuffixed(n: u64) -> Lit {
     Lit::Int(n, IntTy::Unsuffixed)