Support Big Endianness (at least for unions) and add a few tests to v…

…erify it works fine. #190
ColinPitrat · Apr 1, 2021 · 60f0963 · 60f0963
1 parent 40ed93b
commit 60f0963
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Showing 6 changed files with 88 additions and 6 deletions.
diff --git a/src/cap32.h b/src/cap32.h
@@ -28,6 +28,7 @@
 #include <unistd.h>
 #include <string>
 #include <vector>
+#include "SDL_endian.h"
 
 class InputMapper;
 //#define DEBUG
@@ -212,8 +213,13 @@ typedef struct {
    unsigned char *snd_bufferptr;
    union {
       struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
          unsigned int low;
          unsigned int high;
+#else
+         unsigned int high;
+         unsigned int low;
+#endif
       };
       int64_t both;
    } snd_cycle_count_init;
@@ -338,8 +344,13 @@ typedef struct {
 typedef struct {
    union {
       struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
          unsigned int low;
          unsigned int high;
+#else
+         unsigned int high;
+         unsigned int low;
+#endif
       };
       int64_t both;
    } cycle_count;
@@ -349,13 +360,23 @@ typedef struct {
    union {
       unsigned char Index[16];
       struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
          unsigned char TonALo, TonAHi;
          unsigned char TonBLo, TonBHi;
          unsigned char TonCLo, TonCHi;
+#else
+         unsigned char TonAHi, TonALo;
+         unsigned char TonBHi, TonBLo;
+         unsigned char TonCHi, TonCLo;
+#endif
          unsigned char Noise;
          unsigned char Mixer;
          unsigned char AmplitudeA, AmplitudeB, AmplitudeC;
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
          unsigned char EnvelopeLo, EnvelopeHi;
+#else
+         unsigned char EnvelopeHi, EnvelopeLo;
+#endif
          unsigned char EnvType;
          unsigned char PortA;
          unsigned char PortB;

diff --git a/src/crtc.h b/src/crtc.h
@@ -20,28 +20,45 @@
 #define CRTC_H
 
 #include "types.h"
+#include "SDL_endian.h"
 
 // The next 4 bytes must remain together
 typedef union {
    dword combined;
    struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
       byte monVSYNC;
       byte inHSYNC;
+#endif
       union {
          word combined;
          struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
             byte DISPTIMG;
             byte HDSPTIMG;
+#else
+            byte HDSPTIMG;
+            byte DISPTIMG;
+#endif
          };
       } dt;
+#if SDL_BYTEORDER != SDL_LIL_ENDIAN
+      byte inHSYNC;
+      byte monVSYNC;
+#endif
    };
 } t_flags1;
 // The next two bytes must remain together
 typedef union {
    word combined;
    struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
       byte NewDISPTIMG;
       byte NewHDSPTIMG;
+#else
+      byte NewHDSPTIMG;
+      byte NewDISPTIMG;
+#endif
    };
 } t_new_dt;
 

diff --git a/src/psg.cpp b/src/psg.cpp
@@ -27,6 +27,7 @@
 #include "cap32.h"
 #include "z80.h"
 #include "log.h"
+#include "SDL_endian.h"
 
 extern t_CPC CPC;
 extern t_PSG PSG;
@@ -48,8 +49,13 @@ int Level_PP[256];
 
 union TLoopCount {
    struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
       dword Lo;
       dword Hi;
+#else
+      dword Hi;
+      dword Lo;
+#endif
    };
    int64_t Re;
 } LoopCount;
@@ -61,25 +67,40 @@ void (*Case_EnvType)();
 
 union TCounter {
    struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
       word Lo;
       word Hi;
+#else
+      word Hi;
+      word Lo;
+#endif
    };
    dword Re;
 };
 TCounter Ton_Counter_A, Ton_Counter_B, Ton_Counter_C, Noise_Counter;
 
 union TNoise {
    struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
       word Low;
       word Val;
+#else
+      word Val;
+      word Low;
+#endif
    };
    dword Seed;
 } Noise;
 
 union TEnvelopeCounter {
    struct {
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
       dword Lo;
       dword Hi;
+#else
+      dword Hi;
+      dword Lo;
+#endif
    };
    int64_t Re;
 } Envelope_Counter;

diff --git a/src/z80.h b/src/z80.h
@@ -19,7 +19,7 @@
 #ifndef Z80_H
 #define Z80_H
 
-#include "SDL.h"
+#include "SDL_endian.h"
 #include "types.h"
 #include "crtc.h"
 

diff --git a/test/crtc.cpp b/test/crtc.cpp
@@ -30,7 +30,7 @@ TEST_F(CrtcTest, ShiftLittleEndianDwordTriplet)
    EXPECT_EQ(0x01234567, val);
 }
 
-// This test verifies that access to union as they are used extensively in the code works.
+// Verifies that access to t_new_dt union works fine
 TEST_F(CrtcTest, NewDtCombinedAccess)
 {
   t_new_dt new_dt;
@@ -40,3 +40,17 @@ TEST_F(CrtcTest, NewDtCombinedAccess)
 
   EXPECT_EQ(0x0123, new_dt.combined);
 }
+
+// Verifies that access to t_flags1 unions works fine
+TEST_F(CrtcTest, Flags1CombinedAccess)
+{
+  t_flags1 flags1;
+
+  flags1.dt.HDSPTIMG = 0x01;
+  flags1.dt.DISPTIMG = 0x23;
+  flags1.inHSYNC = 0x45;
+  flags1.monVSYNC = 0x67;
+
+  EXPECT_EQ(0x01234567, flags1.combined);
+  EXPECT_EQ(0x0123, flags1.dt.combined);
+}
diff --git a/test/psg.cpp b/test/psg.cpp
@@ -9,14 +9,23 @@ TEST(PsgTest, RegisterAYAlignment)
    t_PSG psg;
    psg.RegisterAY.TonALo = 3;
    psg.RegisterAY.TonAHi = 5;
-   EXPECT_EQ(*reinterpret_cast<word *>(&psg.RegisterAY.TonALo), psg.RegisterAY.TonA);
+   EXPECT_EQ(0x0503, psg.RegisterAY.TonA);
    psg.RegisterAY.TonBLo = 3;
    psg.RegisterAY.TonBHi = 5;
-   EXPECT_EQ(*reinterpret_cast<word *>(&psg.RegisterAY.TonBLo), psg.RegisterAY.TonB);
+   EXPECT_EQ(0x0503, psg.RegisterAY.TonB);
    psg.RegisterAY.TonCLo = 3;
    psg.RegisterAY.TonCHi = 5;
-   EXPECT_EQ(*reinterpret_cast<word *>(&psg.RegisterAY.TonCLo), psg.RegisterAY.TonC);
+   EXPECT_EQ(0x0503, psg.RegisterAY.TonC);
    psg.RegisterAY.EnvelopeLo = 3;
    psg.RegisterAY.EnvelopeHi = 5;
-   EXPECT_EQ(*reinterpret_cast<word *>(&psg.RegisterAY.EnvelopeLo), psg.RegisterAY.Envelope);
+   EXPECT_EQ(0x0503, psg.RegisterAY.Envelope);
+}
+
+TEST(PsgTest, CycleCountCombinedAccess)
+{
+  t_PSG psg;
+  psg.cycle_count.high = 0x00112233;
+  psg.cycle_count.low = 0x44556677;
+
+  EXPECT_EQ(0x0011223344556677, psg.cycle_count.both);
 }