gdb:csky add pseudo regs for float and vector regs

In the existing CSKY architecture, there are at most 32 floating
and 16 vector registers. Float registers's count can be configured
as 16 or 32. In the future, the vector registers's count may be
extended to 32.

The bit width of floating-point register is 64bits, and the bit
width of vector register is 128bit.

Special points: in fr0~fr15 and vr0~vr15, each FRx is the lower
64 bits of the corresponding VRx.

Here, we will split each floating-point and vector register to
32bits wide, add the corresponding pseudo registers, and finally
use them for the dwarf registers.

There are 128 pseudo registers in total, s0~s127, including:
1. s0 and s1 correspond to fr0, s4 and s5 correspond to fr1, and so on.
Every two separated pseudo registers correspond to a float register.
2. s0, s1, s2 and s3 correspond to vr0; s4, s5, s6 and s7 correspond to vr1,
and so on. Every four pseudo registers corresponds to a vector register.

Therefore, in s64~s127, there are general registers that are not actually
used. This part is to prepare for the expansion of vector registers to 32

Therefore, in s64~s127, half of the registers are actually unused. This
part is to prepare for the expansion of the vector register to 32.

2 files changed, 268 insertions, 0 deletions

diff --git a/gdb/csky-tdep.c b/gdb/csky-tdep.c
index 7a9c38c0064..b63ff7ccd44 100644
--- a/gdb/csky-tdep.c
+++ b/gdb/csky-tdep.c
@@ -59,6 +59,7 @@
 #include <vector>
 
 /* Control debugging information emitted in this file.  */
+
 static bool csky_debug = false;
 
 static const reggroup *cr_reggroup;
@@ -363,7 +364,13 @@ static const struct csky_supported_tdesc_register csky_supported_alias_regs[] =
   {"t_pcr",   230},
 };
 
+/* Functions declaration.  */
+
+static const char *
+csky_pseudo_register_name (struct gdbarch *gdbarch, int regno);
+
 /* Get csky supported registers's count for tdesc xml.  */
+
 static int
 csky_get_supported_tdesc_registers_count()
 {
@@ -381,6 +388,7 @@ csky_get_supported_tdesc_registers_count()
 }
 
 /* Return a supported register according to index.  */
+
 static const struct csky_supported_tdesc_register *
 csky_get_supported_register_by_index (int index)
 {
@@ -652,6 +660,15 @@ static const char * const csky_register_names[] =
 static const char *
 csky_register_name (struct gdbarch *gdbarch, int reg_nr)
 {
+  int num_regs = gdbarch_num_regs (gdbarch);
+  int num_pseudo_regs =  gdbarch_num_pseudo_regs (gdbarch);
+
+  if ((reg_nr >= num_regs) && (reg_nr < (num_regs + num_pseudo_regs)))
+    return csky_pseudo_register_name (gdbarch, reg_nr);
+
+  if (tdesc_has_registers (gdbarch_target_desc (gdbarch)))
+    return tdesc_register_name (gdbarch, reg_nr);
+
   if (reg_nr < 0)
     return NULL;
 
@@ -2569,6 +2586,7 @@ csky_print_registers_info (struct gdbarch *gdbarch, struct ui_file *file,
 }
 
 /* Check whether xml has discribled the essential regs.  */
+
 static int
 csky_essential_reg_check (const struct csky_supported_tdesc_register *reg)
 {
@@ -2585,6 +2603,200 @@ csky_essential_reg_check (const struct csky_supported_tdesc_register *reg)
     return 0;
 }
 
+/* Check whether xml has discribled the fr0~fr15 regs.  */
+
+static int
+csky_fr0_fr15_reg_check (const struct csky_supported_tdesc_register *reg) {
+  int i = 0;
+  for (i = 0; i < 16; i++)
+    {
+      if ((strcmp (reg->name, csky_supported_fpu_regs[i].name) == 0)
+          && (csky_supported_fpu_regs[i].num == reg->num))
+        return (1 << i);
+    }
+
+  return 0;
+};
+
+/* Check whether xml has discribled the fr16~fr31 regs.  */
+
+static int
+csky_fr16_fr31_reg_check (const struct csky_supported_tdesc_register *reg) {
+  int i = 0;
+  for (i = 0; i < 16; i++)
+    {
+      if ((strcmp (reg->name, csky_supported_fpu_regs[i + 16].name) == 0)
+          && (csky_supported_fpu_regs[i + 16].num == reg->num))
+        return (1 << i);
+    }
+
+  return 0;
+};
+
+/* Check whether xml has discribled the vr0~vr15 regs.  */
+
+static int
+csky_vr0_vr15_reg_check (const struct csky_supported_tdesc_register *reg) {
+  int i = 0;
+  for (i = 0; i < 16; i++)
+    {
+      if ((strcmp (reg->name, csky_supported_fpu_regs[i + 32].name) == 0)
+          && (csky_supported_fpu_regs[i + 32].num == reg->num))
+        return (1 << i);
+    }
+
+  return 0;
+};
+
+/* Return pseudo reg's name.  */
+
+static const char *
+csky_pseudo_register_name (struct gdbarch *gdbarch, int regno)
+{
+  int num_regs = gdbarch_num_regs (gdbarch);
+  csky_gdbarch_tdep *tdep
+        = (csky_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  regno -= num_regs;
+
+  if (tdep->fv_pseudo_registers_count)
+    {
+      static const char *const fv_pseudo_names[] = {
+        "s0", "s1", "s2", "s3", "s4", "s5", "s6", "s7",
+        "s8", "s9", "s10", "s11", "s12", "s13", "s14", "s15",
+        "s16", "s17", "s18", "s19", "s20", "s21", "s22", "s23",
+        "s24", "s25", "s26", "s27", "s28", "s29", "s30", "s31",
+        "s32", "s33", "s34", "s35", "s36", "s37", "s38", "s39",
+        "s40", "s41", "s42", "s43", "s44", "s45", "s46", "s47",
+        "s48", "s49", "s50", "s51", "s52", "s53", "s54", "s55",
+        "s56", "s57", "s58", "s59", "s60", "s61", "s62", "s63",
+        "s64", "s65", "s66", "s67", "s68", "s69", "s70", "s71",
+        "s72", "s73", "s74", "s75", "s76", "s77", "s78", "s79",
+        "s80", "s81", "s82", "s83", "s84", "s85", "s86", "s87",
+        "s88", "s89", "s90", "s91", "s92", "s93", "s94", "s95",
+        "s96", "s97", "s98", "s99", "s100", "s101", "s102", "s103",
+        "s104", "s105", "s106", "s107", "s108", "s109", "s110", "s111",
+        "s112", "s113", "s114", "s115", "s116", "s117", "s118", "s119",
+        "s120", "s121", "s122", "s123", "s124", "s125", "s126", "s127",
+      };
+
+      if (regno < tdep->fv_pseudo_registers_count)
+        {
+          if ((regno < 64) && ((regno % 4) >= 2) && !tdep->has_vr0)
+            return NULL;
+          else if ((regno >= 64) && ((regno % 4) >= 2))
+            return NULL;
+          else
+            return fv_pseudo_names[regno];
+        }
+    }
+
+  return NULL;
+}
+
+/* Read for csky pseudo regs.  */
+
+static enum register_status
+csky_pseudo_register_read (struct gdbarch *gdbarch,
+                           struct readable_regcache *regcache,
+                           int regnum, gdb_byte *buf)
+{
+  int num_regs = gdbarch_num_regs (gdbarch);
+  csky_gdbarch_tdep *tdep
+        = (csky_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  regnum -= num_regs;
+
+  if (regnum < tdep->fv_pseudo_registers_count)
+    {
+      enum register_status status;
+      int gdb_regnum = 0;
+      int offset = 0;
+      gdb_byte reg_buf[16];
+
+      /* Ensure getting s0~s63 from vrx if tdep->has_vr0 is ture.  */
+      if (tdep->has_vr0)
+        {
+          if (regnum < 64)
+            {
+              gdb_regnum = CSKY_VR0_REGNUM + (regnum / 4);
+              offset = (regnum % 4) * 4;
+            }
+          else
+            {
+              gdb_regnum = CSKY_FR16_REGNUM + ((regnum - 64) / 4);
+              if ((regnum % 4) >= 2)
+                 return REG_UNAVAILABLE;
+              offset = (regnum % 2) * 4;
+            }
+        }
+      else
+        {
+           gdb_regnum = CSKY_FR0_REGNUM + (regnum / 4);
+           if ((regnum % 4) >= 2)
+              return REG_UNAVAILABLE;
+           offset = (regnum % 2) * 4;
+        }
+
+      status = regcache->raw_read (gdb_regnum, reg_buf);
+      if (status == REG_VALID)
+        memcpy (buf, reg_buf + offset, 4);
+      return status;
+    }
+
+  return REG_UNKNOWN;
+}
+
+/* Write for csky pseudo regs.  */
+
+static void
+csky_pseudo_register_write (struct gdbarch *gdbarch, struct regcache *regcache,
+                            int regnum, const gdb_byte *buf)
+{
+  int num_regs = gdbarch_num_regs (gdbarch);
+  csky_gdbarch_tdep *tdep
+        = (csky_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+
+  regnum -= num_regs;
+
+  if (regnum < tdep->fv_pseudo_registers_count)
+    {
+      gdb_byte reg_buf[16];
+      int gdb_regnum = 0;
+      int offset = 0;
+
+      if (tdep->has_vr0)
+        {
+          if (regnum < 64)
+            {
+              gdb_regnum = CSKY_VR0_REGNUM + (regnum / 4);
+              offset = (regnum % 4) * 4;
+            }
+          else
+            {
+              gdb_regnum = CSKY_FR16_REGNUM + ((regnum - 64) / 4);
+              if ((regnum % 4) >= 2)
+                return;
+              offset = (regnum % 2) * 4;
+            }
+        }
+      else
+        {
+           gdb_regnum = CSKY_FR0_REGNUM + (regnum / 4);
+           if ((regnum % 4) >= 2)
+             return;
+           offset = (regnum % 2) * 4;
+        }
+
+      regcache->raw_read (gdb_regnum, reg_buf);
+      memcpy (reg_buf + offset, buf, 4);
+      regcache->raw_write (gdb_regnum, reg_buf);
+      return;
+    }
+
+  return;
+}
+
 /* Initialize the current architecture based on INFO.  If possible,
    re-use an architecture from ARCHES, which is a list of
    architectures already created during this debugging session.
@@ -2602,6 +2814,9 @@ csky_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   unsigned int fpu_hardfp = 0;
   /* Analyze info.target_desc */
   int num_regs = 0;
+  int has_fr0 = 0;
+  int has_fr16 = 0;
+  int has_vr0 = 0;
   tdesc_arch_data_up tdesc_data;
 
   if (tdesc_has_registers (info.target_desc))
@@ -2633,6 +2848,9 @@ csky_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
                                                       tdesc_reg->name);
                   if (numbered) {
                     valid_p |= csky_essential_reg_check (tdesc_reg);
+                    has_fr0 |= csky_fr0_fr15_reg_check (tdesc_reg);
+                    has_fr16 |= csky_fr16_fr31_reg_check (tdesc_reg);
+                    has_vr0 |= csky_vr0_vr15_reg_check (tdesc_reg);
                     if (num_regs < tdesc_reg->num)
                       num_regs = tdesc_reg->num;
                   }
@@ -2685,6 +2903,38 @@ csky_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   tdep->vdsp_version = vdsp_version;
   tdep->fpu_hardfp = fpu_hardfp;
 
+  if (tdesc_data != NULL)
+    {
+      if ((has_vr0 == CSKY_FULL16_ONEHOT_VALUE)
+          && (has_fr16 == CSKY_FULL16_ONEHOT_VALUE))
+        {
+          tdep->has_vr0 = 1;
+          tdep->fv_pseudo_registers_count = 128;
+        }
+      else if ((has_vr0 == CSKY_FULL16_ONEHOT_VALUE)
+               && (has_fr16 != CSKY_FULL16_ONEHOT_VALUE))
+        {
+          tdep->has_vr0 = 1;
+          tdep->fv_pseudo_registers_count = 64;
+        }
+      else if ((has_fr0 == CSKY_FULL16_ONEHOT_VALUE)
+               && (has_vr0 != CSKY_FULL16_ONEHOT_VALUE))
+        {
+          tdep->has_vr0 = 0;
+          tdep->fv_pseudo_registers_count = 64;
+        }
+      else
+        {
+          tdep->has_vr0 = 0;
+          tdep->fv_pseudo_registers_count = 0;
+        }
+    }
+  else
+    {
+      tdep->has_vr0 = 1;
+      tdep->fv_pseudo_registers_count = 64;
+    }
+
   /* Target data types.  */
   set_gdbarch_ptr_bit (gdbarch, 32);
   set_gdbarch_addr_bit (gdbarch, 32);
@@ -2753,6 +3003,17 @@ csky_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
       set_gdbarch_register_type (gdbarch, csky_register_type);
     }
 
+  if (tdep->fv_pseudo_registers_count)
+    {
+      set_gdbarch_num_pseudo_regs (gdbarch,
+                                   tdep->fv_pseudo_registers_count);
+      set_gdbarch_pseudo_register_read (gdbarch,
+                                        csky_pseudo_register_read);
+      set_gdbarch_pseudo_register_write (gdbarch,
+                                         csky_pseudo_register_write);
+      set_tdesc_pseudo_register_name (gdbarch, csky_pseudo_register_name);
+    }
+
   return gdbarch;
 }
 
diff --git a/gdb/csky-tdep.h b/gdb/csky-tdep.h
index adfe9faaa0c..4ff8a6b8613 100644
--- a/gdb/csky-tdep.h
+++ b/gdb/csky-tdep.h
@@ -37,6 +37,10 @@ struct csky_gdbarch_tdep : gdbarch_tdep
   unsigned int fpu_abi;
   unsigned int fpu_hardfp;
   unsigned int vdsp_version;
+
+  /* Save fv_pseudo_registers_count.  */
+  unsigned int has_vr0;
+  unsigned int fv_pseudo_registers_count;
 };
 
 /* Instruction sizes.  */
@@ -101,6 +105,9 @@ enum csky_regnum
 #define CSKY_TDESC_REGS_LR_NUMBERED             (1 << 2)
 #define CSKY_TDESC_REGS_ESSENTIAL_VALUE         (7)
 
+/* For fr0~fr15, fr16~fr31, vr0~vr15 check.  */
+#define CSKY_FULL16_ONEHOT_VALUE   0xffff
+
 /* Number of processor registers w/o ICE registers.  */
 #define CSKY_NUM_REGS (CSKY_MAX_REGS - CSKY_CRBANK_NUM_REGS)