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, 9 insertions, 7 deletions

diff --git a/src/SPI.h b/src/SPI.h
index aee4165..7ed889a 100644
--- a/src/SPI.h
+++ b/src/SPI.h
@@ -51,7 +51,7 @@ public:
     virtual void Reset() = 0;
     virtual void DoSavestate(Savestate* file) = 0;
 
-    virtual u8 Read() { return Data; }
+    virtual u8 Read() const { return Data; }
     virtual void Write(u8 val) = 0;
     virtual void Release() { Hold = false; DataPos = 0; }
 
@@ -76,7 +76,7 @@ public:
     Firmware& GetFirmware() noexcept { return FirmwareData; }
     [[nodiscard]] const Firmware& GetFirmware() const noexcept { return FirmwareData; }
     void SetFirmware(Firmware&& firmware) { FirmwareData = std::move(firmware); }
-    bool IsLoadedFirmwareBuiltIn();
+    bool IsLoadedFirmwareBuiltIn() const;
 
     void Write(u8 val) override;
     void Release() override;
@@ -89,7 +89,7 @@ private:
     u8 StatusReg;
     u32 Addr;
 
-    bool VerifyCRC16(u32 start, u32 offset, u32 len, u32 crcoffset);
+    bool VerifyCRC16(u32 start, u32 offset, u32 len, u32 crcoffset) const;
 };
 
 class PowerMan : public SPIDevice
@@ -100,7 +100,7 @@ public:
     void Reset() override;
     void DoSavestate(Savestate* file) override;
 
-    bool GetBatteryLevelOkay();
+    bool GetBatteryLevelOkay() const;
     void SetBatteryLevelOkay(bool okay);
 
     void Write(u8 val) override;
@@ -121,7 +121,7 @@ public:
     virtual void DoSavestate(Savestate* file) override;
 
     virtual void SetTouchCoords(u16 x, u16 y);
-    virtual void MicInputFrame(s16* data, int samples);
+    virtual void MicInputFrame(const s16* data, int samples);
 
     virtual void Write(u8 val) override;
 
@@ -148,16 +148,18 @@ public:
     FirmwareMem* GetFirmwareMem() { return (FirmwareMem*)Devices[SPIDevice_FirmwareMem]; }
     const FirmwareMem* GetFirmwareMem() const { return (FirmwareMem*)Devices[SPIDevice_FirmwareMem]; }
     PowerMan* GetPowerMan() { return (PowerMan*)Devices[SPIDevice_PowerMan]; }
+    const PowerMan* GetPowerMan() const { return (PowerMan*)Devices[SPIDevice_PowerMan]; }
     TSC* GetTSC() { return (TSC*)Devices[SPIDevice_TSC]; }
+    const TSC* GetTSC() const { return (TSC*)Devices[SPIDevice_TSC]; }
 
     const Firmware& GetFirmware() const { return GetFirmwareMem()->GetFirmware(); }
     Firmware& GetFirmware() { return GetFirmwareMem()->GetFirmware(); }
     void SetFirmware(Firmware&& firmware) { GetFirmwareMem()->SetFirmware(std::move(firmware)); }
 
-    u16 ReadCnt() { return Cnt; }
+    u16 ReadCnt() const { return Cnt; }
     void WriteCnt(u16 val);
 
-    u8 ReadData();
+    u8 ReadData() const;
     void WriteData(u8 val);
 
     void TransferDone(u32 param);