Sprinkle `const` around where appropriate (#1909)

* Sprinkle `const` around where appropriate

- This will make it easier to use `NDS` objects in `const` contexts (e.g. `const` parameters or methods)

* Remove the `const` qualifier on `DSi_DSP::DSPRead16`

- MMIO reads can be non-pure, so this may not be `const` in the future

1 files changed, 7 insertions, 7 deletions

diff --git a/src/DSi_I2C.cpp b/src/DSi_I2C.cpp
index d5ea60c..28f98dc 100644
--- a/src/DSi_I2C.cpp
+++ b/src/DSi_I2C.cpp
@@ -117,20 +117,20 @@ void DSi_BPTWL::DoSavestate(Savestate* file)
 }
 
 // TODO: Needs more investigation on the other bits
-inline bool DSi_BPTWL::GetIRQMode()
+inline bool DSi_BPTWL::GetIRQMode() const
 {
     return Registers[0x12] & 0x01;
 }
 
-u8 DSi_BPTWL::GetBootFlag() { return Registers[0x70]; }
+u8 DSi_BPTWL::GetBootFlag() const { return Registers[0x70]; }
 
-bool DSi_BPTWL::GetBatteryCharging() { return Registers[0x20] >> 7; }
+bool DSi_BPTWL::GetBatteryCharging() const { return Registers[0x20] >> 7; }
 void DSi_BPTWL::SetBatteryCharging(bool charging)
 {
     Registers[0x20] = (((charging ? 0x8 : 0x0) << 4) | (Registers[0x20] & 0x0F));
 }
 
-u8 DSi_BPTWL::GetBatteryLevel() { return Registers[0x20] & 0xF; }
+u8 DSi_BPTWL::GetBatteryLevel() const { return Registers[0x20] & 0xF; }
 void DSi_BPTWL::SetBatteryLevel(u8 batteryLevel)
 {
     Registers[0x20] = ((Registers[0x20] & 0xF0) | (batteryLevel & 0x0F));
@@ -143,13 +143,13 @@ void DSi_BPTWL::SetBatteryLevel(u8 batteryLevel)
 
 }
 
-u8 DSi_BPTWL::GetVolumeLevel() { return Registers[0x40]; }
+u8 DSi_BPTWL::GetVolumeLevel() const { return Registers[0x40]; }
 void DSi_BPTWL::SetVolumeLevel(u8 volume)
 {
     Registers[0x40] = volume & 0x1F;
 }
 
-u8 DSi_BPTWL::GetBacklightLevel() { return Registers[0x41]; }
+u8 DSi_BPTWL::GetBacklightLevel() const { return Registers[0x41]; }
 void DSi_BPTWL::SetBacklightLevel(u8 backlight)
 {
     Registers[0x41] = backlight > 4 ? 4 : backlight;
@@ -246,7 +246,7 @@ void DSi_BPTWL::SetVolumeSwitchReleased(u32 key)
     VolumeSwitchRepeatTime = 0.0;
 }
 
-inline bool DSi_BPTWL::CheckVolumeSwitchKeysValid()
+inline bool DSi_BPTWL::CheckVolumeSwitchKeysValid() const
 {
     bool up = VolumeSwitchKeysDown & (1 << volumeKey_Up);
     bool down = VolumeSwitchKeysDown & (1 << volumeKey_Down);