Experimental code to get a few games working

[virtualjaguar] / src / gpu.cpp

diff --git a/src/gpu.cpp b/src/gpu.cpp
index 464350cf9fbb7453e6da89be7a1563658ffeaad0..53abf8c90bac459fd8427c02f16774973251158f 100644 (file)
--- a/src/gpu.cpp
+++ b/src/gpu.cpp
@@ -1,7 +1,7 @@
 //
 // GPU Core
 //
-// by Cal2
+// Originally by David Raingeard (Cal2)
 // GCC/SDL port by Niels Wagenaar (Linux/WIN32) and Caz (BeOS)
 // Cleanups, endian wrongness, and bad ASM amelioration by James L. Hammons
 // Note: Endian wrongness probably stems from the MAME origins of this emu and
@@ -223,7 +223,8 @@ static void gpu_opcode_store_r15_ri(void);
 static void gpu_opcode_sat24(void);
 static void gpu_opcode_pack(void);
 
-uint8 gpu_opcode_cycles[64] = 
+// This is wrong, since it doesn't take pipeline effects into account. !!! FIX !!!
+/*uint8 gpu_opcode_cycles[64] = 
 {
        3,  3,  3,  3,  3,  3,  3,  3,
        3,  3,  3,  3,  3,  3,  3,  3,
@@ -233,6 +234,21 @@ uint8 gpu_opcode_cycles[64] =
        5,  4,  5,  6,  6,  1,  1,  1,
        1,  2,  2,  2,  1,  1,  9,  3,
        3,  1,  6,  6,  2,  2,  3,  3
+};//*/
+//Here's a QnD kludge...
+//This is wrong, wrong, WRONG, but it seems to work for the time being...
+//(That is, it fixes Flip Out which relies on GPU timing rather than semaphores. Bad developers! Bad!)
+//What's needed here is a way to take pipeline effects into account (including pipeline stalls!)...
+uint8 gpu_opcode_cycles[64] = 
+{
+       1,  1,  1,  1,  1,  1,  1,  1,
+       1,  1,  1,  1,  1,  1,  1,  1,
+       1,  1,  1,  1,  1,  9,  1,  1,
+       1,  1,  1,  1,  1,  1,  1,  1,
+       1,  1,  1,  1,  1,  1,  1,  2,
+       2,  2,  2,  3,  3,  1,  1,  1,
+       1,  1,  1,  1,  1,  1,  4,  1,
+       1,  1,  3,  3,  1,  1,  1,  1
 };
 
 void (*gpu_opcode[64])()= 
@@ -435,9 +451,9 @@ uint16 GPUReadWord(uint32 offset, uint32 who/*=UNKNOWN*/)
                        return data >> 16;
        }
 
-//TEMP--Mirror of F03000?
-if (offset >= 0xF0B000 && offset <= 0xF0BFFF)
-WriteLog("[GPUR16] --> Possible GPU RAM mirror access by %s!", whoName[who]);
+//TEMP--Mirror of F03000? No. Writes only...
+//if (offset >= 0xF0B000 && offset <= 0xF0BFFF)
+//WriteLog("[GPUR16] --> Possible GPU RAM mirror access by %s!", whoName[who]);
 
        return JaguarReadWord(offset, who);
 }
@@ -493,9 +509,9 @@ uint32 GPUReadLong(uint32 offset, uint32 who/*=UNKNOWN*/)
                        return 0;
                }
        }
-//TEMP--Mirror of F03000?
-if (offset >= 0xF0B000 && offset <= 0xF0BFFF)
-       WriteLog("[GPUR32] --> Possible GPU RAM mirror access by %s!\n", whoName[who]);
+//TEMP--Mirror of F03000? No. Writes only...
+//if (offset >= 0xF0B000 && offset <= 0xF0BFFF)
+//     WriteLog("[GPUR32] --> Possible GPU RAM mirror access by %s!\n", whoName[who]);
 /*if (offset >= 0xF1D000 && offset <= 0xF1DFFF)
        WriteLog("[GPUR32] --> Reading from Wavetable ROM!\n");//*/
 
@@ -558,6 +574,10 @@ void GPUWriteWord(uint32 offset, uint16 data, uint32 who/*=UNKNOWN*/)
 /*             offset &= 0xFFF;
                SET16(gpu_ram_8, offset, data);//*/
 
+/*if (offset >= 0xF03214 && offset < 0xF0321F)
+       WriteLog("GPU: Writing WORD (%04X) to GPU RAM (%08X)...\n", data, offset);//*/
+
+
 //This is the same stupid worthless code that was in the DSP!!! AARRRGGGGHHHHH!!!!!!
 /*             if (!gpu_in_exec)
                {
@@ -1465,14 +1485,25 @@ static void gpu_opcode_subc(void)
        UINT32 res = RN - RM - gpu_flag_c;
        UINT32 borrow = gpu_flag_c;
 //     SET_ZNC_SUB(RN, RM, res); //???BUG??? YES!!!
-       SET_ZNC_SUB(RN - borrow, RM, res);
+//No matter how you do it, there is a problem. With below, it's 0-0 with carry,
+//and the one below it it's FFFFFFFF - FFFFFFFF with carry... !!! FIX !!!
+//     SET_ZNC_SUB(RN - borrow, RM, res);
+       SET_ZNC_SUB(RN, RM + borrow, res);
        RN = res;
 #ifdef GPU_DIS_SUBC
        if (doGPUDis)
                WriteLog("[NCZ:%u%u%u, R%02u=%08X, R%02u=%08X]\n", gpu_flag_n, gpu_flag_c, gpu_flag_z, IMM_1, RM, IMM_2, RN);
 #endif
 }
+/*
+N = 5, M = 3, 3 - 5 = -2, C = 1... Or, in our case:
+N = 0, M = 1, 0 - 1 = -1, C = 0!
 
+#define SET_C_SUB(a,b)         (gpu_flag_c = ((UINT32)(b) > (UINT32)(a)))
+#define SET_ZN(r)                      SET_N(r); SET_Z(r)
+#define SET_ZNC_ADD(a,b,r)     SET_N(r); SET_Z(r); SET_C_ADD(a,b)
+#define SET_ZNC_SUB(a,b,r)     SET_N(r); SET_Z(r); SET_C_SUB(a,b)
+*/
 static void gpu_opcode_subq(void)
 {
 #ifdef GPU_DIS_SUBQ
@@ -1593,7 +1624,7 @@ static void gpu_opcode_move_pc(void)
 {
 #ifdef GPU_DIS_MOVEPC
        if (doGPUDis)
-               WriteLog("%06X: MOVE   PC, R%02u [NCZ:%u%u%u, PC=%08X, R%02u=%08X] -> ", gpu_pc-2, IMM_1, IMM_2, gpu_flag_n, gpu_flag_c, gpu_flag_z, gpu_pc-2, IMM_2, RN);
+               WriteLog("%06X: MOVE   PC, R%02u [NCZ:%u%u%u, PC=%08X, R%02u=%08X] -> ", gpu_pc-2, IMM_2, gpu_flag_n, gpu_flag_c, gpu_flag_z, gpu_pc-2, IMM_2, RN);
 #endif
        // Should be previous PC--this might not always be previous instruction!
        // Then again, this will point right at the *current* instruction, i.e., MOVE PC,R!