Various fixes for GPU/DSP DIV instruction, fixes for joypad handling.

[virtualjaguar] / src / gpu.cpp

diff --git a/src/gpu.cpp b/src/gpu.cpp
index 1f1bef9351cbe14eb6ab5ba18a1c94d00d5fa7e8..49a862a1fe945efff93633bd3a1b5810436b357c 100644 (file)
--- a/src/gpu.cpp
+++ b/src/gpu.cpp
@@ -99,8 +99,8 @@
 #define GPU_DIS_SUBQT
 #define GPU_DIS_XOR
 
-//bool doGPUDis = false;
-bool doGPUDis = true;
+bool doGPUDis = false;
+//bool doGPUDis = true;
 #endif
 
 /*
@@ -1192,6 +1192,10 @@ if (gpu_ram_8[0x054] == 0x98 && gpu_ram_8[0x055] == 0x0A && gpu_ram_8[0x056] ==
 /*             gpu_flag_c = (gpu_flag_c ? 1 : 0);
                gpu_flag_z = (gpu_flag_z ? 1 : 0);
                gpu_flag_n = (gpu_flag_n ? 1 : 0);*/
+#if 0
+if (gpu_pc == 0xF03200)
+       doGPUDis = true;
+#endif
 
                uint16_t opcode = GPUReadWord(gpu_pc, GPU);
                uint32_t index = opcode >> 10;
@@ -2188,6 +2192,7 @@ static void gpu_opcode_mult(void)
                WriteLog("%06X: MULT   R%02u, R%02u [NCZ:%u%u%u, R%02u=%08X, R%02u=%08X] -> ", gpu_pc-2, IMM_1, IMM_2, gpu_flag_n, gpu_flag_c, gpu_flag_z, IMM_1, RM, IMM_2, RN);
 #endif
        RN = (uint16_t)RM * (uint16_t)RN;
+//     RN = (RM & 0xFFFF) * (RN & 0xFFFF);
        SET_ZN(RN);
 #ifdef GPU_DIS_MULT
        if (doGPUDis)
@@ -2347,48 +2352,34 @@ static void gpu_opcode_div(void)        // RN / RM
 //       The original tried to get it right by checking to see if the
 //       remainder was negative, but that's too late...
 // The code there should do it now, but I'm not 100% sure...
+// [Now it should be correct, but not displaying correct behavior of the actual
+//  hardware. A step in the right direction.]
 
        if (RM)
        {
                if (gpu_div_control & 0x01)             // 16.16 division
                {
-                       RN = ((uint64_t)RN << 16) / RM;
                        gpu_remain = ((uint64_t)RN << 16) % RM;
+                       RN = ((uint64_t)RN << 16) / RM;
                }
                else
                {
-                       RN = RN / RM;
+                       // We calculate the remainder first because we destroy RN after
+                       // this by assigning it to itself.
                        gpu_remain = RN % RM;
+                       RN = RN / RM;
                }
 
+// What we really should do here is figure out why this condition
+// happens in the real divide unit and emulate *that* behavior.
+#if 0
                if ((gpu_remain - RM) & 0x80000000)     // If the result would have been negative...
                        gpu_remain -= RM;                       // Then make it negative!
+#endif
        }
        else
                RN = 0xFFFFFFFF;
 
-/*     uint32_t _RM=RM;
-       uint32_t _RN=RN;
-
-       if (_RM)
-       {
-               if (gpu_div_control & 1)
-               {
-                       gpu_remain = (((uint64_t)_RN) << 16) % _RM;
-                       if (gpu_remain&0x80000000)
-                               gpu_remain-=_RM;
-                       RN = (((uint64_t)_RN) << 16) / _RM;
-               }
-               else
-               {
-                       gpu_remain = _RN % _RM;
-                       if (gpu_remain&0x80000000)
-                               gpu_remain-=_RM;
-                       RN/=_RM;
-               }
-       }
-       else
-               RN=0xffffffff;*/
 #ifdef GPU_DIS_DIV
        if (doGPUDis)
                WriteLog("[NCZ:%u%u%u, R%02u=%08X, R%02u=%08X] Remainder: %08X\n", gpu_flag_n, gpu_flag_c, gpu_flag_z, IMM_1, RM, IMM_2, RN, gpu_remain);