/* -----------------------------------------------------------------------------
 * $Id: MachRegs.h,v 1.21.2.3 2005/07/13 08:47:05 simonmar Exp $
 *
 * (c) The GHC Team, 1998-1999
 *
 * Registers used in STG code.  Might or might not correspond to
 * actual machine registers.
 *
 * ---------------------------------------------------------------------------*/

#ifndef MACHREGS_H
#define MACHREGS_H

/* This file is #included into Haskell code in the compiler: #defines
 * only in here please.
 */

/* 
 * Defining NO_REGS causes no global registers to be used.  NO_REGS is
 * typically defined by GHC, via a command-line option passed to gcc,
 * when the -funregisterised flag is given.
 *
 * NB. When NO_REGS is on, calling & return conventions may be
 * different.  For example, all function arguments will be passed on
 * the stack, and components of an unboxed tuple will be returned on
 * the stack rather than in registers.
 */
#ifndef NO_REGS

/* NOTE: when testing the platform in this file we must test either
 * *_HOST_ARCH and *_TARGET_ARCH, depending on whether COMPILING_GHC
 * is set.  This is because when we're compiling the RTS and HC code,
 * the platform we're running on is the HOST, but when compiling GHC
 * we want to know about the register mapping on the TARGET platform.
 */
#ifdef COMPILING_GHC
#define alpha_REGS    alpha_TARGET_ARCH
#define hppa1_1_REGS  hppa1_1_TARGET_ARCH
#define i386_REGS     i386_TARGET_ARCH
#define x86_64_REGS   x86_64_TARGET_ARCH
#define m68k_REGS     m68k_TARGET_ARCH
#define mips_REGS     (mipsel_TARGET_ARCH || mipseb_TARGET_ARCH)
#define powerpc_REGS  (powerpc_TARGET_ARCH || powerpc64_TARGET_ARCH || rs6000_TARGET_ARCH)
#define ia64_REGS     ia64_TARGET_ARCH
#define sparc_REGS    sparc_TARGET_ARCH
#define darwin_REGS   darwin_TARGET_OS
#else
#define alpha_REGS    alpha_HOST_ARCH
#define hppa1_1_REGS  hppa1_1_HOST_ARCH
#define i386_REGS     i386_HOST_ARCH
#define x86_64_REGS   x86_64_HOST_ARCH
#define m68k_REGS     m68k_HOST_ARCH
#define mips_REGS     (mipsel_HOST_ARCH || mipseb_HOST_ARCH)
#define powerpc_REGS  (powerpc_HOST_ARCH || powerpc64_HOST_ARCH || rs6000_HOST_ARCH)
#define ia64_REGS     ia64_HOST_ARCH
#define sparc_REGS    sparc_HOST_ARCH
#define darwin_REGS   darwin_HOST_OS
#endif

/* ----------------------------------------------------------------------------
   Caller saves and callee-saves regs.
   
   Caller-saves regs have to be saved around C-calls made from STG
   land, so this file defines CALLER_SAVES_<reg> for each <reg> that
   is designated caller-saves in that machine's C calling convention.

   Additionally, the following macros should be defined when

     CALLER_SAVES_USER		one or more of R<n>, F, D
 			        are caller-saves.

     CALLER_SAVES_SYSTEM        one or more of Sp, SpLim, Hp, HpLim
     				are caller-saves.

   This is so that the callWrapper mechanism knows which kind of
   wrapper to generate for certain types of C call.
   -------------------------------------------------------------------------- */

/* -----------------------------------------------------------------------------
   The DEC Alpha register mapping

   Alpha registers
   \tr{$9}--\tr{$14} are our ``prize'' callee-save registers.  
   \tr{$15} is the frame pointer, and \tr{$16}--\tr{$21} are argument
   registers.  (These are off-limits.)  We can steal some of the \tr{$22}-and-up 
   caller-save registers provided we do the appropriate save/restore stuff.
   
   \tr{$f2}--\tr{$f9} are some callee-save floating-point registers.
   
   We cannot use \tr{$23} (aka t9), \tr{$24} (aka t10), \tr{$25} (aka
   t11), \tr{$27} (aka pv), or \tr{$28} (aka at), because they are
   occasionally required by the assembler to handle non-primitive
   instructions (e.g. ldb, remq).  Sigh!
   
   Cheat sheet for GDB:
   
   GDB	here	Main map
   ===	====	========
   s5	$14	R1
   t1	$2	R2
   t2	$3	R3
   t3	$4	R4
   t4	$5	R5
   t5	$6	R6
   t6	$7	R7
   t7	$8	R8
   s0	$9	Sp
   s2	$11	SpLim
   s3	$12	Hp   
   s4	$13	HpLim
   t8	$22	NCG_reserved
   t12	$27	NCG_reserved
   -------------------------------------------------------------------------- */

#if alpha_REGS
# define REG(x) __asm__("$" #x)

#  define CALLER_SAVES_R2
#  define CALLER_SAVES_R3
#  define CALLER_SAVES_R4
#  define CALLER_SAVES_R5
#  define CALLER_SAVES_R6
#  define CALLER_SAVES_R7
#  define CALLER_SAVES_R8
  
#  define CALLER_SAVES_USER
  
#  define REG_R1	14
#  define REG_R2    	2
#  define REG_R3    	3
#  define REG_R4    	4
#  define REG_R5    	5
#  define REG_R6    	6
#  define REG_R7    	7
#  define REG_R8    	8
  
#  define REG_F1	f2
#  define REG_F2	f3
#  define REG_F3	f4
#  define REG_F4	f5
  
#  define REG_D1	f6
#  define REG_D2	f7
  
#  define REG_Sp    	9
#  define REG_SpLim     11

#  define REG_Hp	12
#  define REG_HpLim	13
  
#  define NCG_Reserved_I1 22
#  define NCG_Reserved_I2 27
#  define NCG_Reserved_F1 f29
#  define NCG_Reserved_F2 f30

#endif /* alpha_REGS */

/* -----------------------------------------------------------------------------
   The HP-PA register mapping

   We cater for HP-PA 1.1.
   
   \tr{%r0}--\tr{%r1} are special.
   \tr{%r2} is the return pointer.
   \tr{%r3} is the frame pointer.
   \tr{%r4}--\tr{%r18} are callee-save registers.
   \tr{%r19} is a linkage table register for HPUX 8.0 shared libraries.
   \tr{%r20}--\tr{%r22} are caller-save registers.
   \tr{%r23}--\tr{%r26} are parameter registers.
   \tr{%r27} is a global data pointer.
   \tr{%r28}--\tr{%r29} are temporaries.
   \tr{%r30} is the stack pointer.
   \tr{%r31} is a temporary.
   
   \tr{%fr12}--\tr{%fr15} are some callee-save floating-point registers.
   \tr{%fr8}--\tr{%fr11} are some available caller-save fl-pt registers.
   -------------------------------------------------------------------------- */

#if hppa1_1_REGS

#define REG(x) __asm__("%" #x)

#define REG_R1		r11
#define REG_R2    	r12
#define REG_R3    	r13
#define REG_R4    	r14
#define REG_R5    	r15
#define REG_R6    	r16
#define REG_R7    	r17
#define REG_R8    	r18

#define REG_F1		fr12
#define REG_F2		fr12R
#define REG_F3		fr13
#define REG_F4		fr13R

#define REG_D1		fr20	/* L & R */
#define REG_D2		fr21	/* L & R */

#define REG_Sp    	r4
#define REG_SpLim    	r6

#define REG_Hp	    	r7
#define REG_HpLim	r8

#define NCG_Reserved_I1 r28
#define NCG_Reserved_I2	r29
#define NCG_Reserved_F1	fr8
#define NCG_Reserved_F2	fr8R
#define NCG_Reserved_D1	fr10
#define NCG_Reserved_D2	fr11

#endif /* hppa */

/* -----------------------------------------------------------------------------
   The x86 register mapping

   Ok, we've only got 6 general purpose registers, a frame pointer and a
   stack pointer.  \tr{%eax} and \tr{%edx} are return values from C functions,
   hence they get trashed across ccalls and are caller saves. \tr{%ebx},
   \tr{%esi}, \tr{%edi}, \tr{%ebp} are all callee-saves.

   Reg     STG-Reg
   ---------------
   ebx     Base
   ebp     Sp
   esi     R1
   edi     Hp

   Leaving SpLim, and HpLim out of the picture.
   -------------------------------------------------------------------------- */


#if i386_REGS

#define REG(x) __asm__("%" #x)

#ifndef not_doing_dynamic_linking
#define REG_Base    ebx
#endif
#define REG_Sp	    ebp

#ifndef STOLEN_X86_REGS
#define STOLEN_X86_REGS 4
#endif

#if STOLEN_X86_REGS >= 3
# define REG_R1	    esi
#endif

#if STOLEN_X86_REGS >= 4
# define REG_Hp     edi
#endif

#define MAX_REAL_VANILLA_REG 1	/* always, since it defines the entry conv */
#define MAX_REAL_FLOAT_REG   0
#define MAX_REAL_DOUBLE_REG  0
#define MAX_REAL_LONG_REG    0

#endif /* iX86 */

/* -----------------------------------------------------------------------------
  The x86-64 register mapping

  		callee-saves
  %rax
  %rbx		YES
  %rcx          arg reg, caller-saves
  %rdx		arg reg, caller-saves
  %rsi		arg reg, caller-saves
  %rdi		arg reg, caller-saves
  %rbp		YES (our *prime* register)
  %rsp		(unavailable - stack pointer)
  %r8           arg reg, caller-saves
  %r9		arg reg, caller-saves
  %r10          caller-saves
  %r11		caller-saves
  %r12		YES
  %r13		YES
  %r14		YES
  %r15		YES

  %xmm0-7       arg regs, caller-saves
  %xmm8-15      caller-saves

  A better reg mapping might be:

      %rbp  Sp
      %rbx  R1
      %r8   R2
      %r9   R3
      %r10  R4
      %r12  Hp
      %r14  SpLim
      %r15  HpLim
      %xmm8-11   F1-F4
      %xmm12-13  D1-D2

  Use the caller-saves regs for Rn, because we don't always have to
  save those (as opposed to Sp/Hp/SpLim etc. which always have to be
  saved).

  --------------------------------------------------------------------------- */

#if x86_64_REGS

#define REG(x) __asm__("%" #x)

#define REG_Base  rbx
#define REG_Sp    rbp
#define REG_Hp    r12
#define REG_R1    r13
#define REG_SpLim r14
#define REG_HpLim r15
/* ToDo: try R2/R3 instead of SpLim/HpLim? */

#define MAX_REAL_VANILLA_REG 1
#define MAX_REAL_FLOAT_REG   0
#define MAX_REAL_DOUBLE_REG  0
#define MAX_REAL_LONG_REG    0

#endif /* x86_64 */

/* -----------------------------------------------------------------------------
   The Motorola 680x0 register mapping

   A Sun3 (mc680x0) has eight address registers, \tr{a0} to \tr{a7}, and
   eight data registers, \tr{d0} to \tr{d7}.  Address operations have to
   be done through address registers; data registers are used for
   comparison values and data.
   
   Here's the register-usage picture for m68k boxes with GCC.

   \begin{tabular}{ll}
   a0 & used directly by GCC \\
   a1 & used directly by GCC \\
   \\
   a2..a5 & callee-saved: available for STG registers \\
   & (a5 may be special, ``global'' register for PIC?) \\
   \\
   a6 & C-stack frame pointer \\
   a7 & C-stack pointer \\
   \\
   d0 & used directly by GCC \\
   d1 & used directly by GCC \\
   d2 & really needed for local optimisation by GCC \\
   \\
   d3..d7 & callee-saved: available for STG registers
   \\
   fp0 & call-clobbered \\
   fp1 & call-clobbered \\
   fp2..fp7 & callee-saved: available for STG registers
   \end{tabular}
   -------------------------------------------------------------------------- */

#if m68k_REGS

#define REG(x) __asm__(#x)

#define REG_Base	a2

#define REG_Sp		a3
#define REG_SpLim	d3

#define REG_Hp	    	d4
#define REG_HpLim       d5

#define REG_R1    	a5
#define REG_R2    	d6
#define MAX_REAL_VANILLA_REG 2

#define REG_Ret		d7

#define REG_F1		fp2
#define REG_F2		fp3
#define REG_F3		fp4
#define REG_F4		fp5

#define REG_D1		fp6
#define REG_D2		fp7

#endif /* m68k */

/* -----------------------------------------------------------------------------
   The DECstation (MIPS) register mapping

   Here's at least some simple stuff about registers on a MIPS.
   
   \tr{s0}--\tr{s7} are callee-save integer registers; they are our
   ``prize'' stolen registers.  There is also a wad of callee-save
   floating-point registers, \tr{$f20}--\tr{$f31}; we'll use some of
   those.
   
   \tr{t0}--\tr{t9} are caller-save (``temporary?'') integer registers.
   We can steal some, but we might have to save/restore around ccalls.
   -------------------------------------------------------------------------- */

#if mips_REGS

#define REG(x) __asm__("$" #x)

#define CALLER_SAVES_R1
#define CALLER_SAVES_R2
#define CALLER_SAVES_R3
#define CALLER_SAVES_R4
#define CALLER_SAVES_R5
#define CALLER_SAVES_R6
#define CALLER_SAVES_R7
#define CALLER_SAVES_R8

#define CALLER_SAVES_USER

#define REG_R1		9
#define REG_R2    	10
#define REG_R3    	11
#define REG_R4    	12
#define REG_R5    	13
#define REG_R6    	14
#define REG_R7    	15
#define REG_R8    	24

#define REG_F1		f20
#define REG_F2		f22
#define REG_F3		f24
#define REG_F4		f26

#define REG_D1		f28
#define REG_D2		f30

#define REG_Sp    	16
#define REG_SpLim    	18

#define REG_Hp	    	19
#define REG_HpLim	20

#endif /* mipse[lb] */

/* -----------------------------------------------------------------------------
   The PowerPC register mapping

   0		system glue?	(caller-save, volatile)
   1		SP		(callee-save, non-volatile)
   2            AIX, powerpc64-linux:
                    RTOC        (a strange special case)
                darwin:         
                                (caller-save, volatile)
                powerpc32-linux:
                                reserved for use by system
                    
   3-10		args/return	(caller-save, volatile)
   11,12	system glue?	(caller-save, volatile)
   13           on 64-bit:      reserved for thread state pointer
                on 32-bit:      (callee-save, non-volatile)
   14-31			(callee-save, non-volatile)
   
   f0				(caller-save, volatile)
   f1-f13	args/return	(caller-save, volatile)
   f14-f31			(callee-save, non-volatile)
   
   \tr{14}--\tr{31} are wonderful callee-save registers on all ppc OSes.
   \tr{0}--\tr{12} are caller-save registers.
   
   \tr{%f14}--\tr{%f31} are callee-save floating-point registers.
   
   We can do the Whole Business with callee-save registers only!
   -------------------------------------------------------------------------- */

#if powerpc_REGS

#define REG(x) __asm__(#x)

#define REG_R1		r14
#define REG_R2    	r15
#define REG_R3    	r16
#define REG_R4    	r17
#define REG_R5    	r18
#define REG_R6    	r19
#define REG_R7    	r20
#define REG_R8    	r21

#if darwin_REGS

#define REG_F1		f14
#define REG_F2		f15
#define REG_F3		f16
#define REG_F4		f17

#define REG_D1		f18
#define REG_D2		f19

#else

#define REG_F1		fr14
#define REG_F2		fr15
#define REG_F3		fr16
#define REG_F4		fr17

#define REG_D1		fr18
#define REG_D2		fr19

#endif

#define REG_Sp    	r22
#define REG_SpLim    	r24

#define REG_Hp	    	r25
#define REG_HpLim	r26

#define REG_Base        r27

#endif /* powerpc */

/* -----------------------------------------------------------------------------
   The IA64 register mapping

   We place the general registers in the locals area of the register stack,
   so that the call mechanism takes care of saving them for us.  We reserve
   the first 16 for gcc's use - since gcc uses the highest used register to
   determine the register stack frame size, this gives us a constant size
   register stack frame.
   
   \tr{f16-f32} are the callee-saved floating point registers.
   -------------------------------------------------------------------------- */

#if ia64_REGS

#define REG(x) __asm__(#x)

#define REG_R1		loc16
#define REG_R2		loc17
#define REG_R3		loc18
#define REG_R4		loc19
#define REG_R5		loc20
#define REG_R6		loc21
#define REG_R7		loc22
#define REG_R8		loc23

#define REG_F1		f16
#define REG_F2		f17
#define REG_F3		f18
#define REG_F4		f19

#define REG_D1		f20
#define REG_D2		f21

#define REG_Sp		loc24
#define REG_SpLim	loc26

#define REG_Hp		loc27
#define REG_HpLim	loc28

#endif /* ia64 */

/* -----------------------------------------------------------------------------
   The Sun SPARC register mapping

   The SPARC register (window) story: Remember, within the Haskell
   Threaded World, we essentially ``shut down'' the register-window
   mechanism---the window doesn't move at all while in this World.  It
   *does* move, of course, if we call out to arbitrary~C...
   
   The %i, %l, and %o registers (8 each) are the input, local, and
   output registers visible in one register window.  The 8 %g (global)
   registers are visible all the time.
   
   %o0..%o7 	       	not available; can be zapped by callee
   			  (%o6 is C-stack ptr; %o7 hold ret addrs)
   %i0..%i7            	available (except %i6 is used as frame ptr)
   			  (and %i7 tends to have ret-addr-ish things)
   %l0..%l7	       	available
   %g0..%g4 		not available; prone to stomping by division, etc.
   %g5..%g7 		not available; reserved for the OS

   Note: %g3 is *definitely* clobbered in the builtin divide code (and
   our save/restore machinery is NOT GOOD ENOUGH for that); discretion
   being the better part of valor, we also don't take %g4.

   The paired nature of the floating point registers causes complications for
   the native code generator.  For convenience, we pretend that the first 22
   fp regs %f0 .. %f21 are actually 11 double regs, and the remaining 10 are
   float (single) regs.  The NCG acts accordingly.  That means that the 
   following FP assignment is rather fragile, and should only be changed
   with extreme care.  The current scheme is:

      %f0 /%f1    FP return from C
      %f2 /%f3    D1
      %f4 /%f5    D2
      %f6 /%f7    ncg double spill tmp #1
      %f8 /%f9    ncg double spill tmp #2
      %f10/%f11   allocatable
      %f12/%f13   allocatable
      %f14/%f15   allocatable
      %f16/%f17   allocatable
      %f18/%f19   allocatable
      %f20/%f21   allocatable

      %f22        F1
      %f23        F2
      %f24        F3
      %f25        F4
      %f26        ncg single spill tmp #1
      %f27        ncg single spill tmp #2
      %f28        allocatable
      %f29        allocatable
      %f30        allocatable
      %f31        allocatable

   -------------------------------------------------------------------------- */

#if sparc_REGS

#define REG(x) __asm__("%" #x)

#define CALLER_SAVES_USER

#define CALLER_SAVES_F1
#define CALLER_SAVES_F2
#define CALLER_SAVES_F3
#define CALLER_SAVES_F4
#define CALLER_SAVES_D1
#define CALLER_SAVES_D2

#define REG_R1	    	l1
#define REG_R2    	l2
#define REG_R3    	l3
#define REG_R4    	l4
#define REG_R5    	l5
#define REG_R6    	i5

#define REG_F1	    	f22
#define REG_F2	    	f23
#define REG_F3	    	f24
#define REG_F4	    	f25
#define REG_D1	    	f2
#define REG_D2	    	f4

#define REG_Sp    	i0
#define REG_SpLim    	i2

#define REG_Hp	    	i3
#define REG_HpLim	i4

#define NCG_SpillTmp_I1	g1
#define NCG_SpillTmp_I2	g2
#define NCG_SpillTmp_F1	f26
#define NCG_SpillTmp_F2 f27
#define NCG_SpillTmp_D1	f6
#define NCG_SpillTmp_D2	f8

#define NCG_FirstFloatReg f22

#endif /* sparc */

#endif /* NO_REGS */

/* -----------------------------------------------------------------------------
 * These constants define how many stg registers will be used for
 * passing arguments (and results, in the case of an unboxed-tuple
 * return).
 *
 * We usually set MAX_REAL_VANILLA_REG and co. to be the number of the
 * highest STG register to occupy a real machine register, otherwise
 * the calling conventions will needlessly shuffle data between the
 * stack and memory-resident STG registers.  We might occasionally
 * set these macros to other values for testing, though.
 *
 * Registers above these values might still be used, for instance to
 * communicate with PrimOps and RTS functions.
 */

#ifndef MAX_REAL_VANILLA_REG
#  if   defined(REG_R8)
#  define MAX_REAL_VANILLA_REG 8
#  elif defined(REG_R7)
#  define MAX_REAL_VANILLA_REG 7
#  elif defined(REG_R6)
#  define MAX_REAL_VANILLA_REG 6
#  elif defined(REG_R5)
#  define MAX_REAL_VANILLA_REG 5
#  elif defined(REG_R4)
#  define MAX_REAL_VANILLA_REG 4
#  elif defined(REG_R3)
#  define MAX_REAL_VANILLA_REG 3
#  elif defined(REG_R2)
#  define MAX_REAL_VANILLA_REG 2
#  elif defined(REG_R1)
#  define MAX_REAL_VANILLA_REG 1
#  else
#  define MAX_REAL_VANILLA_REG 0
#  endif
#endif

#ifndef MAX_REAL_FLOAT_REG
#  if   defined(REG_F4)
#  define MAX_REAL_FLOAT_REG 4
#  elif defined(REG_F3)
#  define MAX_REAL_FLOAT_REG 3
#  elif defined(REG_F2)
#  define MAX_REAL_FLOAT_REG 2
#  elif defined(REG_F1)
#  define MAX_REAL_FLOAT_REG 1
#  else
#  define MAX_REAL_FLOAT_REG 0
#  endif
#endif

#ifndef MAX_REAL_DOUBLE_REG
#  if   defined(REG_D2)
#  define MAX_REAL_DOUBLE_REG 2
#  elif defined(REG_D1)
#  define MAX_REAL_DOUBLE_REG 1
#  else
#  define MAX_REAL_DOUBLE_REG 0
#  endif
#endif

#ifndef MAX_REAL_LONG_REG
#  if   defined(REG_L1)
#  define MAX_REAL_LONG_REG 1
#  else
#  define MAX_REAL_LONG_REG 0
#  endif
#endif

/* define NO_ARG_REGS if we have no argument registers at all (we can
 * optimise certain code paths using this predicate).
 */
#if MAX_REAL_VANILLA_REG < 2
#define NO_ARG_REGS 
#else
#undef NO_ARG_REGS
#endif

#endif /* MACHREGS_H */
