sh2: handle some branch exceptions

[picodrive.git] / cpu / sh2 / mame / sh2pico.c

diff --git a/cpu/sh2/mame/sh2pico.c b/cpu/sh2/mame/sh2pico.c
index 37ade45..174d469 100644 (file)
--- a/cpu/sh2/mame/sh2pico.c
+++ b/cpu/sh2/mame/sh2pico.c
@@ -17,12 +17,46 @@ typedef unsigned short UINT16;
 typedef unsigned char  UINT8;
 #endif
 
-#define RB(sh2, a) p32x_sh2_read8(a,sh2)
-#define RW(sh2, a) p32x_sh2_read16(a,sh2)
-#define RL(sh2, a) p32x_sh2_read32(a,sh2)
-#define WB(sh2, a, d) p32x_sh2_write8(a,d,sh2)
-#define WW(sh2, a, d) p32x_sh2_write16(a,d,sh2)
-#define WL(sh2, a, d) p32x_sh2_write32(a,d,sh2)
+#ifdef DRC_SH2
+
+// this nasty conversion is needed for drc-expecting memhandlers
+#define MAKE_READFUNC(name, cname) \
+static inline unsigned int name(SH2 *sh2, unsigned int a) \
+{ \
+       unsigned int ret; \
+       sh2->sr |= sh2->icount << 12; \
+       ret = cname(a, sh2); \
+       sh2->icount = (signed int)sh2->sr >> 12; \
+       sh2->sr &= 0x3f3; \
+       return ret; \
+}
+
+#define MAKE_WRITEFUNC(name, cname) \
+static inline void name(SH2 *sh2, unsigned int a, unsigned int d) \
+{ \
+       sh2->sr |= sh2->icount << 12; \
+       cname(a, d, sh2); \
+       sh2->icount = (signed int)sh2->sr >> 12; \
+       sh2->sr &= 0x3f3; \
+}
+
+MAKE_READFUNC(RB, p32x_sh2_read8)
+MAKE_READFUNC(RW, p32x_sh2_read16)
+MAKE_READFUNC(RL, p32x_sh2_read32)
+MAKE_WRITEFUNC(WB, p32x_sh2_write8)
+MAKE_WRITEFUNC(WW, p32x_sh2_write16)
+MAKE_WRITEFUNC(WL, p32x_sh2_write32)
+
+#else
+
+#define RB(sh2, a) p32x_sh2_read8(a, sh2)
+#define RW(sh2, a) p32x_sh2_read16(a, sh2)
+#define RL(sh2, a) p32x_sh2_read32(a, sh2)
+#define WB(sh2, a, d) p32x_sh2_write8(a, d, sh2)
+#define WW(sh2, a, d) p32x_sh2_write16(a, d, sh2)
+#define WL(sh2, a, d) p32x_sh2_write32(a, d, sh2)
+
+#endif
 
 // some stuff from sh2comn.h
 #define T      0x00000001
@@ -71,14 +105,13 @@ static unsigned int op_refs[0x10000];
 
 #include "sh2.c"
 
-#ifndef DRC_SH2
 #ifndef DRC_CMP
 
-int sh2_execute(SH2 *sh2, int cycles)
+int sh2_execute_interpreter(SH2 *sh2, int cycles)
 {
        UINT32 opcode;
 
-       sh2->icount = sh2->cycles_timeslice = cycles;
+       sh2->icount = cycles;
 
        if (sh2->icount <= 0)
                goto out;
@@ -89,6 +122,18 @@ int sh2_execute(SH2 *sh2, int cycles)
                {
                        sh2->ppc = sh2->delay;
                        opcode = RW(sh2, sh2->delay);
+
+                       // TODO: more branch types
+                       if ((opcode >> 13) == 5) { // BRA/BSR
+                               sh2->r[15] -= 4;
+                               WL(sh2, sh2->r[15], sh2->sr);
+                               sh2->r[15] -= 4;
+                               WL(sh2, sh2->r[15], sh2->pc);
+                               sh2->pc = RL(sh2, sh2->vbr + 6 * 4);
+                               sh2->icount -= 5;
+                               opcode = 9; // NOP
+                       }
+
                        sh2->pc -= 2;
                }
                else
@@ -134,12 +179,12 @@ int sh2_execute(SH2 *sh2, int cycles)
        while (sh2->icount > 0 || sh2->delay);  /* can't interrupt before delay */
 
 out:
-       return sh2->cycles_timeslice - sh2->icount;
+       return sh2->icount;
 }
 
 #else // if DRC_CMP
 
-int sh2_execute(SH2 *sh2, int cycles)
+int sh2_execute_interpreter(SH2 *sh2, int cycles)
 {
        static unsigned int base_pc_[2] = { 0, 0 };
        static unsigned int end_pc_[2] = { 0, 0 };
@@ -233,11 +278,10 @@ int sh2_execute(SH2 *sh2, int cycles)
        while (1);
 
 out:
-       return sh2->cycles_timeslice - sh2->icount;
+       return sh2->icount;
 }
 
 #endif // DRC_CMP
-#endif // DRC_SH2
 
 #ifdef SH2_STATS
 #include <stdio.h>