mesa/src/gallium/auxiliary/rtasm/rtasm_ppc_spe.c

/*
 * (C) Copyright IBM Corporation 2008
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, and/or sell copies of the Software, and to permit persons to whom
 * the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
 * AUTHORS, COPYRIGHT HOLDERS, AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 * USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file
 * Real-time assembly generation interface for Cell B.E. SPEs.
 *
 * \author Ian Romanick <idr@us.ibm.com>
 * \author Brian Paul
 */


#include <stdio.h>
#include "pipe/p_compiler.h"
#include "util/u_memory.h"
#include "rtasm_ppc_spe.h"


#ifdef GALLIUM_CELL
/**
 * SPE instruction types
 *
 * There are 6 primary instruction encodings used on the Cell's SPEs.  Each of
 * the following unions encodes one type.
 *
 * \bug
 * If, at some point, we start generating SPE code from a little-endian host
 * these unions will not work.
 */
/*@{*/
/**
 * Encode one output register with two input registers
 */
union spe_inst_RR {
    uint32_t bits;
    struct {
	unsigned op:11;
	unsigned rB:7;
	unsigned rA:7;
	unsigned rT:7;
    } inst;
};


/**
 * Encode one output register with three input registers
 */
union spe_inst_RRR {
    uint32_t bits;
    struct {
	unsigned op:4;
	unsigned rT:7;
	unsigned rB:7;
	unsigned rA:7;
	unsigned rC:7;
    } inst;
};


/**
 * Encode one output register with one input reg. and a 7-bit signed immed
 */
union spe_inst_RI7 {
    uint32_t bits;
    struct {
	unsigned op:11;
	unsigned i7:7;
	unsigned rA:7;
	unsigned rT:7;
    } inst;
};


/**
 * Encode one output register with one input reg. and an 8-bit signed immed
 */
union spe_inst_RI8 {
    uint32_t bits;
    struct {
	unsigned op:10;
	unsigned i8:8;
	unsigned rA:7;
	unsigned rT:7;
    } inst;
};


/**
 * Encode one output register with one input reg. and a 10-bit signed immed
 */
union spe_inst_RI10 {
    uint32_t bits;
    struct {
	unsigned op:8;
	unsigned i10:10;
	unsigned rA:7;
	unsigned rT:7;
    } inst;
};


/**
 * Encode one output register with a 16-bit signed immediate
 */
union spe_inst_RI16 {
    uint32_t bits;
    struct {
	unsigned op:9;
	unsigned i16:16;
	unsigned rT:7;
    } inst;
};


/**
 * Encode one output register with a 18-bit signed immediate
 */
union spe_inst_RI18 {
    uint32_t bits;
    struct {
	unsigned op:7;
	unsigned i18:18;
	unsigned rT:7;
    } inst;
};
/*@}*/


static void
indent(const struct spe_function *p)
{
   int i;
   for (i = 0; i < p->indent; i++) {
      putchar(' ');
   }
}


static const char *
rem_prefix(const char *longname)
{
   return longname + 4;
}


static void emit_RR(struct spe_function *p, unsigned op, unsigned rT,
		    unsigned rA, unsigned rB, const char *name)
{
    union spe_inst_RR inst;
    inst.inst.op = op;
    inst.inst.rB = rB;
    inst.inst.rA = rA;
    inst.inst.rT = rT;
    p->store[p->num_inst++] = inst.bits;
    assert(p->num_inst <= p->max_inst);
    if (p->print) {
       indent(p);
       printf("%s\t$%d, $%d, $%d\n", rem_prefix(name), rT, rA, rB);
    }
}


static void emit_RRR(struct spe_function *p, unsigned op, unsigned rT,
                     unsigned rA, unsigned rB, unsigned rC, const char *name)
{
    union spe_inst_RRR inst;
    inst.inst.op = op;
    inst.inst.rT = rT;
    inst.inst.rB = rB;
    inst.inst.rA = rA;
    inst.inst.rC = rC;
    p->store[p->num_inst++] = inst.bits;
    assert(p->num_inst <= p->max_inst);
    if (p->print) {
       indent(p);
       printf("%s\t$%d, $%d, $%d, $%d\n", rem_prefix(name), rT, rA, rB, rC);
    }
}


static void emit_RI7(struct spe_function *p, unsigned op, unsigned rT,
		     unsigned rA, int imm, const char *name)
{
    union spe_inst_RI7 inst;
    inst.inst.op = op;
    inst.inst.i7 = imm;
    inst.inst.rA = rA;
    inst.inst.rT = rT;
    p->store[p->num_inst++] = inst.bits;
    assert(p->num_inst <= p->max_inst);
    if (p->print) {
       indent(p);
       printf("%s\t$%d, $%d, 0x%x\n", rem_prefix(name), rT, rA, imm);
    }
}



static void emit_RI8(struct spe_function *p, unsigned op, unsigned rT,
		     unsigned rA, int imm, const char *name)
{
    union spe_inst_RI8 inst;
    inst.inst.op = op;
    inst.inst.i8 = imm;
    inst.inst.rA = rA;
    inst.inst.rT = rT;
    p->store[p->num_inst++] = inst.bits;
    assert(p->num_inst <= p->max_inst);
    if (p->print) {
       indent(p);
       printf("%s\t$%d, $%d, 0x%x\n", rem_prefix(name), rT, rA, imm);
    }
}



static void emit_RI10(struct spe_function *p, unsigned op, unsigned rT,
		      unsigned rA, int imm, const char *name)
{
    union spe_inst_RI10 inst;
    inst.inst.op = op;
    inst.inst.i10 = imm;
    inst.inst.rA = rA;
    inst.inst.rT = rT;
    p->store[p->num_inst++] = inst.bits;
    assert(p->num_inst <= p->max_inst);
    if (p->print) {
       indent(p);
       if (strcmp(name, "spe_lqd") == 0 ||
           strcmp(name, "spe_stqd") == 0)
          printf("%s\t$%d, 0x%x($%d)\n", rem_prefix(name), rT, imm, rA);
       else
          printf("%s\t$%d, $%d, 0x%x\n", rem_prefix(name), rT, rA, imm);
    }
}


static void emit_RI16(struct spe_function *p, unsigned op, unsigned rT,
		      int imm, const char *name)
{
    union spe_inst_RI16 inst;
    inst.inst.op = op;
    inst.inst.i16 = imm;
    inst.inst.rT = rT;
    p->store[p->num_inst++] = inst.bits;
    assert(p->num_inst <= p->max_inst);
    if (p->print) {
       indent(p);
       printf("%s\t$%d, 0x%x\n", rem_prefix(name), rT, imm);
    }
}


static void emit_RI18(struct spe_function *p, unsigned op, unsigned rT,
		      int imm, const char *name)
{
    union spe_inst_RI18 inst;
    inst.inst.op = op;
    inst.inst.i18 = imm;
    inst.inst.rT = rT;
    p->store[p->num_inst++] = inst.bits;
    assert(p->num_inst <= p->max_inst);
    if (p->print) {
       indent(p);
       printf("%s\t$%d, 0x%x\n", rem_prefix(name), rT, imm);
    }
}




#define EMIT_(_name, _op) \
void _name (struct spe_function *p, unsigned rT) \
{ \
   emit_RR(p, _op, rT, 0, 0, __FUNCTION__); \
}

#define EMIT_R(_name, _op) \
void _name (struct spe_function *p, unsigned rT, unsigned rA) \
{ \
   emit_RR(p, _op, rT, rA, 0, __FUNCTION__);                 \
}

#define EMIT_RR(_name, _op) \
void _name (struct spe_function *p, unsigned rT, unsigned rA, unsigned rB) \
{ \
   emit_RR(p, _op, rT, rA, rB, __FUNCTION__);                \
}

#define EMIT_RRR(_name, _op) \
void _name (struct spe_function *p, unsigned rT, unsigned rA, unsigned rB, unsigned rC) \
{ \
   emit_RRR(p, _op, rT, rA, rB, rC, __FUNCTION__);           \
}

#define EMIT_RI7(_name, _op) \
void _name (struct spe_function *p, unsigned rT, unsigned rA, int imm) \
{ \
   emit_RI7(p, _op, rT, rA, imm, __FUNCTION__);              \
}

#define EMIT_RI8(_name, _op, bias) \
void _name (struct spe_function *p, unsigned rT, unsigned rA, int imm) \
{ \
   emit_RI8(p, _op, rT, rA, bias - imm, __FUNCTION__);       \
}

#define EMIT_RI10(_name, _op) \
void _name (struct spe_function *p, unsigned rT, unsigned rA, int imm) \
{ \
   emit_RI10(p, _op, rT, rA, imm, __FUNCTION__);             \
}

#define EMIT_RI16(_name, _op) \
void _name (struct spe_function *p, unsigned rT, int imm) \
{ \
   emit_RI16(p, _op, rT, imm, __FUNCTION__);                 \
}

#define EMIT_RI18(_name, _op) \
void _name (struct spe_function *p, unsigned rT, int imm) \
{ \
   emit_RI18(p, _op, rT, imm, __FUNCTION__);                 \
}

#define EMIT_I16(_name, _op) \
void _name (struct spe_function *p, int imm) \
{ \
   emit_RI16(p, _op, 0, imm, __FUNCTION__);                  \
}

#include "rtasm_ppc_spe.h"


/**
 * Initialize an spe_function.
 * \param code_size  size of instruction buffer to allocate, in bytes.
 */
void spe_init_func(struct spe_function *p, unsigned code_size)
{
    p->store = align_malloc(code_size, 16);
    p->num_inst = 0;
    p->max_inst = code_size / SPE_INST_SIZE;

    /* Conservatively treat R0 - R2 and R80 - R127 as non-volatile.
     */
    p->regs[0] = ~7;
    p->regs[1] = (1U << (80 - 64)) - 1;

    p->print = false;
    p->indent = 0;
}


void spe_release_func(struct spe_function *p)
{
    assert(p->num_inst <= p->max_inst);
    if (p->store != NULL) {
        align_free(p->store);
    }
    p->store = NULL;
}


/**
 * Allocate a SPE register.
 * \return register index or -1 if none left.
 */
int spe_allocate_available_register(struct spe_function *p)
{
   unsigned i;
   for (i = 0; i < SPE_NUM_REGS; i++) {
      const uint64_t mask = (1ULL << (i % 64));
      const unsigned idx = i / 64;

      assert(idx < 2);
      if ((p->regs[idx] & mask) != 0) {
         p->regs[idx] &= ~mask;
         return i;
      }
   }

   return -1;
}


/**
 * Mark the given SPE register as "allocated".
 */
int spe_allocate_register(struct spe_function *p, int reg)
{
   const unsigned idx = reg / 64;
   const unsigned bit = reg % 64;

   assert(reg < SPE_NUM_REGS);
   assert((p->regs[idx] & (1ULL << bit)) != 0);

   p->regs[idx] &= ~(1ULL << bit);
   return reg;
}


/**
 * Mark the given SPE register as "unallocated".
 */
void spe_release_register(struct spe_function *p, int reg)
{
   const unsigned idx = reg / 64;
   const unsigned bit = reg % 64;

   assert(idx < 2);

   assert(reg < SPE_NUM_REGS);
   assert((p->regs[idx] & (1ULL << bit)) == 0);

   p->regs[idx] |= (1ULL << bit);
}


void
spe_print_code(struct spe_function *p, boolean enable)
{
   p->print = enable;
}


void
spe_indent(struct spe_function *p, int spaces)
{
   p->indent += spaces;
}


extern void
spe_comment(struct spe_function *p, int rel_indent, const char *s)
{
   if (p->print) {
      p->indent += rel_indent;
      indent(p);
      p->indent -= rel_indent;
      printf("# %s\n", s);
   }
}


/**
 * For branch instructions:
 * \param d  if 1, disable interupts if branch is taken
 * \param e  if 1, enable interupts if branch is taken
 * If d and e are both zero, don't change interupt status (right?)
 */

/** Branch Indirect to address in rA */
void spe_bi(struct spe_function *p, unsigned rA, int d, int e)
{
   emit_RI7(p, 0x1a8, 0, rA, (d << 5) | (e << 4), __FUNCTION__);
}

/** Interupt Return */
void spe_iret(struct spe_function *p, unsigned rA, int d, int e)
{
   emit_RI7(p, 0x1aa, 0, rA, (d << 5) | (e << 4), __FUNCTION__);
}

/** Branch indirect and set link on external data */
void spe_bisled(struct spe_function *p, unsigned rT, unsigned rA, int d,
		int e)
{
   emit_RI7(p, 0x1ab, rT, rA, (d << 5) | (e << 4), __FUNCTION__);
}

/** Branch indirect and set link.  Save PC in rT, jump to rA. */
void spe_bisl(struct spe_function *p, unsigned rT, unsigned rA, int d,
		int e)
{
   emit_RI7(p, 0x1a9, rT, rA, (d << 5) | (e << 4), __FUNCTION__);
}

/** Branch indirect if zero word.  If rT.word[0]==0, jump to rA. */
void spe_biz(struct spe_function *p, unsigned rT, unsigned rA, int d, int e)
{
   emit_RI7(p, 0x128, rT, rA, (d << 5) | (e << 4), __FUNCTION__);
}

/** Branch indirect if non-zero word.  If rT.word[0]!=0, jump to rA. */
void spe_binz(struct spe_function *p, unsigned rT, unsigned rA, int d, int e)
{
   emit_RI7(p, 0x129, rT, rA, (d << 5) | (e << 4), __FUNCTION__);
}

/** Branch indirect if zero halfword.  If rT.halfword[1]==0, jump to rA. */
void spe_bihz(struct spe_function *p, unsigned rT, unsigned rA, int d, int e)
{
   emit_RI7(p, 0x12a, rT, rA, (d << 5) | (e << 4), __FUNCTION__);
}

/** Branch indirect if non-zero halfword.  If rT.halfword[1]!=0, jump to rA. */
void spe_bihnz(struct spe_function *p, unsigned rT, unsigned rA, int d, int e)
{
   emit_RI7(p, 0x12b, rT, rA, (d << 5) | (e << 4), __FUNCTION__);
}


/* Hint-for-branch instructions
 */
#if 0
hbr;
hbra;
hbrr;
#endif


/* Control instructions
 */
#if 0
stop;
EMIT_RR  (spe_stopd, 0x140);
EMIT_    (spe_lnop,  0x001);
EMIT_    (spe_nop,   0x201);
sync;
EMIT_    (spe_dsync, 0x003);
EMIT_R   (spe_mfspr, 0x00c);
EMIT_R   (spe_mtspr, 0x10c);
#endif


/**
 ** Helper / "macro" instructions.
 ** Use somewhat verbose names as a reminder that these aren't native
 ** SPE instructions.
 **/


void
spe_load_float(struct spe_function *p, unsigned rT, float x)
{
   if (x == 0.0f) {
      spe_il(p, rT, 0x0);
   }
   else if (x == 0.5f) {
      spe_ilhu(p, rT, 0x3f00);
   }
   else if (x == 1.0f) {
      spe_ilhu(p, rT, 0x3f80);
   }
   else if (x == -1.0f) {
      spe_ilhu(p, rT, 0xbf80);
   }
   else {
      union {
         float f;
         unsigned u;
      } bits;
      bits.f = x;
      spe_ilhu(p, rT, bits.u >> 16);
      spe_iohl(p, rT, bits.u & 0xffff);
   }
}


void
spe_load_int(struct spe_function *p, unsigned rT, int i)
{
   if (-32768 <= i && i <= 32767) {
      spe_il(p, rT, i);
   }
   else {
      spe_ilhu(p, rT, i >> 16);
      if (i & 0xffff)
         spe_iohl(p, rT, i & 0xffff);
   }
}


void
spe_splat(struct spe_function *p, unsigned rT, unsigned rA)
{
   spe_ila(p, rT, 66051);
   spe_shufb(p, rT, rA, rA, rT);
}


void
spe_complement(struct spe_function *p, unsigned rT)
{
   spe_nor(p, rT, rT, rT);
}


void
spe_move(struct spe_function *p, unsigned rT, unsigned rA)
{
   spe_ori(p, rT, rA, 0);
}


void
spe_zero(struct spe_function *p, unsigned rT)
{
   spe_xor(p, rT, rT, rT);
}


void
spe_splat_word(struct spe_function *p, unsigned rT, unsigned rA, int word)
{
   assert(word >= 0);
   assert(word <= 3);

   if (word == 0) {
      int tmp1 = rT;
      spe_ila(p, tmp1, 66051);
      spe_shufb(p, rT, rA, rA, tmp1);
   }
   else {
      /* XXX review this, we may not need the rotqbyi instruction */
      int tmp1 = rT;
      int tmp2 = spe_allocate_available_register(p);

      spe_ila(p, tmp1, 66051);
      spe_rotqbyi(p, tmp2, rA, 4 * word);
      spe_shufb(p, rT, tmp2, tmp2, tmp1);

      spe_release_register(p, tmp2);
   }
}

/* For each 32-bit float element of rA and rB, choose the smaller of the
 * two, compositing them into the rT register.
 * 
 * The Float Compare Greater Than (fcgt) instruction will put 1s into
 * compare_reg where rA > rB, and 0s where rA <= rB.
 *
 * Then the Select Bits (selb) instruction will take bits from rA where
 * compare_reg is 0, and from rB where compare_reg is 1; i.e., from rA
 * where rA <= rB and from rB where rB > rA, which is exactly the
 * "min" operation.
 *
 * The compare_reg could in many cases be the same as rT, unless
 * rT == rA || rt == rB.  But since this is common in constructions
 * like "x = min(x, a)", we always allocate a new register to be safe.
 */
void 
spe_float_min(struct spe_function *p, unsigned int rT, unsigned int rA, unsigned int rB)
{
   unsigned int compare_reg = spe_allocate_available_register(p);
   spe_fcgt(p, compare_reg, rA, rB);
   spe_selb(p, rT, rA, rB, compare_reg);
   spe_release_register(p, compare_reg);
}

/* For each 32-bit float element of rA and rB, choose the greater of the
 * two, compositing them into the rT register.
 * 
 * The logic is similar to that of spe_float_min() above; the only
 * difference is that the registers on spe_selb() have been reversed,
 * so that the larger of the two is selected instead of the smaller.
 */
void 
spe_float_max(struct spe_function *p, unsigned int rT, unsigned int rA, unsigned int rB)
{
   unsigned int compare_reg = spe_allocate_available_register(p);
   spe_fcgt(p, compare_reg, rA, rB);
   spe_selb(p, rT, rB, rA, compare_reg);
   spe_release_register(p, compare_reg);
}

#endif /* GALLIUM_CELL */