path: root/includes/stg/MachRegs.h

/* -----------------------------------------------------------------------------
 *
 * (c) The GHC Team, 1998-2014
 *
 * Registers used in STG code.  Might or might not correspond to
 * actual machine registers.
 *
 * Do not #include this file directly: #include "Rts.h" instead.
 *
 * To understand the structure of the RTS headers, see the wiki:
 *   https://gitlab.haskell.org/ghc/ghc/wikis/commentary/source-tree/includes
 *
 * ---------------------------------------------------------------------------*/

#pragma once

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

/*
 * Undefine these as a precaution: some of them were found to be
 * defined by system headers on ARM/Linux.
 */
#undef REG_R1
#undef REG_R2
#undef REG_R3
#undef REG_R4
#undef REG_R5
#undef REG_R6
#undef REG_R7
#undef REG_R8
#undef REG_R9
#undef REG_R10

/*
 * Defining MACHREGS_NO_REGS to 1 causes no global registers to be used.
 * MACHREGS_NO_REGS is typically controlled by NO_REGS, which is
 * typically defined by GHC, via a command-line option passed to gcc,
 * when the -funregisterised flag is given.
 *
 * NB. When MACHREGS_NO_REGS to 1, 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.
 */
#if MACHREGS_NO_REGS == 1

/* Nothing */

#elif MACHREGS_NO_REGS == 0

/* ----------------------------------------------------------------------------
   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.

   As it stands, the only registers that are ever marked caller saves
   are the RX, FX, DX and USER registers; as a result, if you
   decide to caller save a system register (e.g. SP, HP, etc), note that
   this code path is completely untested! -- EZY

   See Note [Register parameter passing] for details.
   -------------------------------------------------------------------------- */

/* -----------------------------------------------------------------------------
   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 out of the picture.
   -------------------------------------------------------------------------- */

#if defined(MACHREGS_i386)

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

#if !defined(not_doing_dynamic_linking)
#define REG_Base    ebx
#endif
#define REG_Sp      ebp

#if !defined(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 REG_MachSp  esp

#define REG_XMM1    xmm0
#define REG_XMM2    xmm1
#define REG_XMM3    xmm2
#define REG_XMM4    xmm3

#define REG_YMM1    ymm0
#define REG_YMM2    ymm1
#define REG_YMM3    ymm2
#define REG_YMM4    ymm3

#define REG_ZMM1    zmm0
#define REG_ZMM2    zmm1
#define REG_ZMM3    zmm2
#define REG_ZMM4    zmm3

#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
#define MAX_REAL_XMM_REG     4
#define MAX_REAL_YMM_REG     4
#define MAX_REAL_ZMM_REG     4

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

  %rax          caller-saves, don't steal this one
  %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

  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).

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

#elif defined(MACHREGS_x86_64)

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

#define REG_Base  r13
#define REG_Sp    rbp
#define REG_Hp    r12
#define REG_R1    rbx
#define REG_R2    r14
#define REG_R3    rsi
#define REG_R4    rdi
#define REG_R5    r8
#define REG_R6    r9
#define REG_SpLim r15
#define REG_MachSp  rsp

/*
Map both Fn and Dn to register xmmn so that we can pass a function any
combination of up to six Float# or Double# arguments without touching
the stack. See Note [Overlapping global registers] for implications.
*/

#define REG_F1    xmm1
#define REG_F2    xmm2
#define REG_F3    xmm3
#define REG_F4    xmm4
#define REG_F5    xmm5
#define REG_F6    xmm6

#define REG_D1    xmm1
#define REG_D2    xmm2
#define REG_D3    xmm3
#define REG_D4    xmm4
#define REG_D5    xmm5
#define REG_D6    xmm6

#define REG_XMM1    xmm1
#define REG_XMM2    xmm2
#define REG_XMM3    xmm3
#define REG_XMM4    xmm4
#define REG_XMM5    xmm5
#define REG_XMM6    xmm6

#define REG_YMM1    ymm1
#define REG_YMM2    ymm2
#define REG_YMM3    ymm3
#define REG_YMM4    ymm4
#define REG_YMM5    ymm5
#define REG_YMM6    ymm6

#define REG_ZMM1    zmm1
#define REG_ZMM2    zmm2
#define REG_ZMM3    zmm3
#define REG_ZMM4    zmm4
#define REG_ZMM5    zmm5
#define REG_ZMM6    zmm6

#if !defined(mingw32_HOST_OS)
#define CALLER_SAVES_R3
#define CALLER_SAVES_R4
#endif
#define CALLER_SAVES_R5
#define CALLER_SAVES_R6

#define CALLER_SAVES_F1
#define CALLER_SAVES_F2
#define CALLER_SAVES_F3
#define CALLER_SAVES_F4
#define CALLER_SAVES_F5
#if !defined(mingw32_HOST_OS)
#define CALLER_SAVES_F6
#endif

#define CALLER_SAVES_D1
#define CALLER_SAVES_D2
#define CALLER_SAVES_D3
#define CALLER_SAVES_D4
#define CALLER_SAVES_D5
#if !defined(mingw32_HOST_OS)
#define CALLER_SAVES_D6
#endif

#define CALLER_SAVES_XMM1
#define CALLER_SAVES_XMM2
#define CALLER_SAVES_XMM3
#define CALLER_SAVES_XMM4
#define CALLER_SAVES_XMM5
#if !defined(mingw32_HOST_OS)
#define CALLER_SAVES_XMM6
#endif

#define CALLER_SAVES_YMM1
#define CALLER_SAVES_YMM2
#define CALLER_SAVES_YMM3
#define CALLER_SAVES_YMM4
#define CALLER_SAVES_YMM5
#if !defined(mingw32_HOST_OS)
#define CALLER_SAVES_YMM6
#endif

#define CALLER_SAVES_ZMM1
#define CALLER_SAVES_ZMM2
#define CALLER_SAVES_ZMM3
#define CALLER_SAVES_ZMM4
#define CALLER_SAVES_ZMM5
#if !defined(mingw32_HOST_OS)
#define CALLER_SAVES_ZMM6
#endif

#define MAX_REAL_VANILLA_REG 6
#define MAX_REAL_FLOAT_REG   6
#define MAX_REAL_DOUBLE_REG  6
#define MAX_REAL_LONG_REG    0
#define MAX_REAL_XMM_REG     6
#define MAX_REAL_YMM_REG     6
#define MAX_REAL_ZMM_REG     6

/* -----------------------------------------------------------------------------
   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)
                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!
   -------------------------------------------------------------------------- */

#elif defined(MACHREGS_powerpc)

#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
#define REG_R9          r22
#define REG_R10         r23

#define REG_F1          fr14
#define REG_F2          fr15
#define REG_F3          fr16
#define REG_F4          fr17
#define REG_F5          fr18
#define REG_F6          fr19

#define REG_D1          fr20
#define REG_D2          fr21
#define REG_D3          fr22
#define REG_D4          fr23
#define REG_D5          fr24
#define REG_D6          fr25

#define REG_Sp          r24
#define REG_SpLim       r25
#define REG_Hp          r26
#define REG_Base        r27

#define MAX_REAL_FLOAT_REG   6
#define MAX_REAL_DOUBLE_REG  6

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

   !! IMPORTANT: if you change this register mapping you must also update
                 compiler/GHC/CmmToAsm/SPARC/Regs.hs. That file handles the
                 mapping for the NCG. This one only affects via-c code.

   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.

      zero: always zero
   scratch: volatile across C-fn calls. used by linker.
       app: usable by application
    system: reserved for system

     alloc: allocated to in the register allocator, intra-closure only

                GHC usage     v8 ABI        v9 ABI
   Global
     %g0        zero        zero          zero
     %g1        alloc       scratch       scrach
     %g2        alloc       app           app
     %g3        alloc       app           app
     %g4        alloc       app           scratch
     %g5                    system        scratch
     %g6                    system        system
     %g7                    system        system

   Output: can be zapped by callee
     %o0-o5     alloc       caller saves
     %o6                    C stack ptr
     %o7                    C ret addr

   Local: maintained by register windowing mechanism
     %l0        alloc
     %l1        R1
     %l2        R2
     %l3        R3
     %l4        R4
     %l5        R5
     %l6        alloc
     %l7        alloc

   Input
     %i0        Sp
     %i1        Base
     %i2        SpLim
     %i3        Hp
     %i4        alloc
     %i5        R6
     %i6                    C frame ptr
     %i7                    C ret addr

   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

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

#elif defined(MACHREGS_sparc)

#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

/* for each of the double arg regs,
   Dn_2 is the high half. */

#define REG_D1          f2
#define REG_D1_2        f3

#define REG_D2          f4
#define REG_D2_2        f5

#define REG_Sp          i0
#define REG_SpLim       i2

#define REG_Hp          i3

#define REG_Base        i1

#define NCG_FirstFloatReg f22

/* -----------------------------------------------------------------------------
   The ARM EABI register mapping

   Here we consider ARM mode (i.e. 32bit isns)
   and also CPU with full VFPv3 implementation

   ARM registers (see Chapter 5.1 in ARM IHI 0042D and
   Section 9.2.2 in ARM Software Development Toolkit Reference Guide)

   r15  PC         The Program Counter.
   r14  LR         The Link Register.
   r13  SP         The Stack Pointer.
   r12  IP         The Intra-Procedure-call scratch register.
   r11  v8/fp      Variable-register 8.
   r10  v7/sl      Variable-register 7.
   r9   v6/SB/TR   Platform register. The meaning of this register is
                   defined by the platform standard.
   r8   v5         Variable-register 5.
   r7   v4         Variable register 4.
   r6   v3         Variable register 3.
   r5   v2         Variable register 2.
   r4   v1         Variable register 1.
   r3   a4         Argument / scratch register 4.
   r2   a3         Argument / scratch register 3.
   r1   a2         Argument / result / scratch register 2.
   r0   a1         Argument / result / scratch register 1.

   VFPv2/VFPv3/NEON registers
   s0-s15/d0-d7/q0-q3    Argument / result/ scratch registers
   s16-s31/d8-d15/q4-q7  callee-saved registers (must be preserved across
                         subroutine calls)

   VFPv3/NEON registers (added to the VFPv2 registers set)
   d16-d31/q8-q15        Argument / result/ scratch registers
   ----------------------------------------------------------------------------- */

#elif defined(MACHREGS_arm)

#define REG(x) __asm__(#x)

#define REG_Base        r4
#define REG_Sp          r5
#define REG_Hp          r6
#define REG_R1          r7
#define REG_R2          r8
#define REG_R3          r9
#define REG_R4          r10
#define REG_SpLim       r11

#if !defined(arm_HOST_ARCH_PRE_ARMv6)
/* d8 */
#define REG_F1    s16
#define REG_F2    s17
/* d9 */
#define REG_F3    s18
#define REG_F4    s19

#define REG_D1    d10
#define REG_D2    d11
#endif

/* -----------------------------------------------------------------------------
   The ARMv8/AArch64 ABI register mapping

   The AArch64 provides 31 64-bit general purpose registers
   and 32 128-bit SIMD/floating point registers.

   General purpose registers (see Chapter 5.1.1 in ARM IHI 0055B)

   Register | Special | Role in the procedure call standard
   ---------+---------+------------------------------------
     SP     |         | The Stack Pointer
     r30    |  LR     | The Link Register
     r29    |  FP     | The Frame Pointer
   r19-r28  |         | Callee-saved registers
     r18    |         | The Platform Register, if needed;
            |         | or temporary register
     r17    |  IP1    | The second intra-procedure-call temporary register
     r16    |  IP0    | The first intra-procedure-call scratch register
    r9-r15  |         | Temporary registers
     r8     |         | Indirect result location register
    r0-r7   |         | Parameter/result registers


   FPU/SIMD registers

   s/d/q/v0-v7    Argument / result/ scratch registers
   s/d/q/v8-v15   callee-saved registers (must be preserved across subroutine calls,
                  but only bottom 64-bit value needs to be preserved)
   s/d/q/v16-v31  temporary registers

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

#elif defined(MACHREGS_aarch64)

#define REG(x) __asm__(#x)

#define REG_Base        r19
#define REG_Sp          r20
#define REG_Hp          r21
#define REG_R1          r22
#define REG_R2          r23
#define REG_R3          r24
#define REG_R4          r25
#define REG_R5          r26
#define REG_R6          r27
#define REG_SpLim       r28

#define REG_F1          s8
#define REG_F2          s9
#define REG_F3          s10
#define REG_F4          s11

#define REG_D1          d12
#define REG_D2          d13
#define REG_D3          d14
#define REG_D4          d15

/* -----------------------------------------------------------------------------
   The s390x register mapping

   Register    | Role(s)                                 | Call effect
   ------------+-------------------------------------+-----------------
   r0,r1       | -                                       | caller-saved
   r2          | Argument / return value                 | caller-saved
   r3,r4,r5    | Arguments                               | caller-saved
   r6          | Argument                                | callee-saved
   r7...r11    | -                                       | callee-saved
   r12         | (Commonly used as GOT pointer)          | callee-saved
   r13         | (Commonly used as literal pool pointer) | callee-saved
   r14         | Return address                          | caller-saved
   r15         | Stack pointer                           | callee-saved
   f0          | Argument / return value                 | caller-saved
   f2,f4,f6    | Arguments                               | caller-saved
   f1,f3,f5,f7 | -                                       | caller-saved
   f8...f15    | -                                       | callee-saved
   v0...v31    | -                                       | caller-saved

   Each general purpose register r0 through r15 as well as each floating-point
   register f0 through f15 is 64 bits wide. Each vector register v0 through v31
   is 128 bits wide.

   Note, the vector registers v0 through v15 overlap with the floating-point
   registers f0 through f15.

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

#elif defined(MACHREGS_s390x)

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

#define REG_Base        r7
#define REG_Sp          r8
#define REG_Hp          r10
#define REG_R1          r11
#define REG_R2          r12
#define REG_R3          r13
#define REG_R4          r6
#define REG_R5          r2
#define REG_R6          r3
#define REG_R7          r4
#define REG_R8          r5
#define REG_SpLim       r9
#define REG_MachSp      r15

#define REG_F1          f8
#define REG_F2          f9
#define REG_F3          f10
#define REG_F4          f11
#define REG_F5          f0
#define REG_F6          f1

#define REG_D1          f12
#define REG_D2          f13
#define REG_D3          f14
#define REG_D4          f15
#define REG_D5          f2
#define REG_D6          f3

#define CALLER_SAVES_R5
#define CALLER_SAVES_R6
#define CALLER_SAVES_R7
#define CALLER_SAVES_R8

#define CALLER_SAVES_F5
#define CALLER_SAVES_F6

#define CALLER_SAVES_D5
#define CALLER_SAVES_D6

/* -----------------------------------------------------------------------------
   The riscv64 register mapping

   Register    | Role(s)                                 | Call effect
   ------------+-----------------------------------------+-------------
   zero        | Hard-wired zero                         | -
   ra          | Return address                          | caller-saved
   sp          | Stack pointer                           | callee-saved
   gp          | Global pointer                          | callee-saved
   tp          | Thread pointer                          | callee-saved
   t0,t1,t2    | -                                       | caller-saved
   s0          | Frame pointer                           | callee-saved
   s1          | -                                       | callee-saved
   a0,a1       | Arguments / return values               | caller-saved
   a2..a7      | Arguments                               | caller-saved
   s2..s11     | -                                       | callee-saved
   t3..t6      | -                                       | caller-saved
   ft0..ft7    | -                                       | caller-saved
   fs0,fs1     | -                                       | callee-saved
   fa0,fa1     | Arguments / return values               | caller-saved
   fa2..fa7    | Arguments                               | caller-saved
   fs2..fs11   | -                                       | callee-saved
   ft8..ft11   | -                                       | caller-saved

   Each general purpose register as well as each floating-point
   register is 64 bits wide.

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

#elif defined(MACHREGS_riscv64)

#define REG(x) __asm__(#x)

#define REG_Base        s1
#define REG_Sp          s2
#define REG_Hp          s3
#define REG_R1          s4
#define REG_R2          s5
#define REG_R3          s6
#define REG_R4          s7
#define REG_R5          s8
#define REG_R6          s9
#define REG_R7          s10
#define REG_SpLim       s11

#define REG_F1          fs0
#define REG_F2          fs1
#define REG_F3          fs2
#define REG_F4          fs3
#define REG_F5          fs4
#define REG_F6          fs5

#define REG_D1          fs6
#define REG_D2          fs7
#define REG_D3          fs8
#define REG_D4          fs9
#define REG_D5          fs10
#define REG_D6          fs11

#define MAX_REAL_FLOAT_REG   6
#define MAX_REAL_DOUBLE_REG  6

#else

#error Cannot find platform to give register info for

#endif

#else

#error Bad MACHREGS_NO_REGS value

#endif

/* -----------------------------------------------------------------------------
 * 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.
 */

#if !defined(MAX_REAL_VANILLA_REG)
#  if   defined(REG_R10)
#  define MAX_REAL_VANILLA_REG 10
#  elif   defined(REG_R9)
#  define MAX_REAL_VANILLA_REG 9
#  elif   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

#if !defined(MAX_REAL_FLOAT_REG)
#  if   defined(REG_F7)
#  error Please manually define MAX_REAL_FLOAT_REG for this architecture
#  elif defined(REG_F6)
#  define MAX_REAL_FLOAT_REG 6
#  elif defined(REG_F5)
#  define MAX_REAL_FLOAT_REG 5
#  elif 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

#if !defined(MAX_REAL_DOUBLE_REG)
#  if   defined(REG_D7)
#  error Please manually define MAX_REAL_DOUBLE_REG for this architecture
#  elif defined(REG_D6)
#  define MAX_REAL_DOUBLE_REG 6
#  elif defined(REG_D5)
#  define MAX_REAL_DOUBLE_REG 5
#  elif defined(REG_D4)
#  define MAX_REAL_DOUBLE_REG 4
#  elif defined(REG_D3)
#  define MAX_REAL_DOUBLE_REG 3
#  elif 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

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

#if !defined(MAX_REAL_XMM_REG)
#  if   defined(REG_XMM6)
#  define MAX_REAL_XMM_REG 6
#  elif defined(REG_XMM5)
#  define MAX_REAL_XMM_REG 5
#  elif defined(REG_XMM4)
#  define MAX_REAL_XMM_REG 4
#  elif defined(REG_XMM3)
#  define MAX_REAL_XMM_REG 3
#  elif defined(REG_XMM2)
#  define MAX_REAL_XMM_REG 2
#  elif defined(REG_XMM1)
#  define MAX_REAL_XMM_REG 1
#  else
#  define MAX_REAL_XMM_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