root/arch/mips/fw/lib/call_o32.S

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  *      O32 interface for the 64 (or N32) ABI.
   4  *
   5  *      Copyright (C) 2002, 2014  Maciej W. Rozycki
   6  */
   7 
   8 #include <asm/asm.h>
   9 #include <asm/regdef.h>
  10 
  11 /* O32 register size.  */
  12 #define O32_SZREG       4
  13 /* Maximum number of arguments supported.  Must be even!  */
  14 #define O32_ARGC        32
  15 /* Number of static registers we save.  */
  16 #define O32_STATC       11
  17 /* Argument area frame size.  */
  18 #define O32_ARGSZ       (O32_SZREG * O32_ARGC)
  19 /* Static register save area frame size.  */
  20 #define O32_STATSZ      (SZREG * O32_STATC)
  21 /* Stack pointer register save area frame size.  */
  22 #define O32_SPSZ        SZREG
  23 /* Combined area frame size.  */
  24 #define O32_FRAMESZ     (O32_ARGSZ + O32_SPSZ + O32_STATSZ)
  25 /* Switched stack frame size.  */
  26 #define O32_NFRAMESZ    (O32_ARGSZ + O32_SPSZ)
  27 
  28                 .text
  29 
  30 /*
  31  * O32 function call dispatcher, for interfacing 32-bit ROM routines.
  32  *
  33  * The standard 64 (N32) calling sequence is supported, with a0 holding
  34  * a function pointer, a1 a pointer to the new stack to call the
  35  * function with or 0 if no stack switching is requested, a2-a7 -- the
  36  * function call's first six arguments, and the stack -- the remaining
  37  * arguments (up to O32_ARGC, including a2-a7).  Static registers, gp
  38  * and fp are preserved, v0 holds the result.  This code relies on the
  39  * called o32 function for sp and ra restoration and this dispatcher has
  40  * to be placed in a KSEGx (or KUSEG) address space.  Any pointers
  41  * passed have to point to addresses within one of these spaces as well.
  42  */
  43 NESTED(call_o32, O32_FRAMESZ, ra)
  44                 REG_SUBU        sp,O32_FRAMESZ
  45 
  46                 REG_S           ra,O32_FRAMESZ-1*SZREG(sp)
  47                 REG_S           fp,O32_FRAMESZ-2*SZREG(sp)
  48                 REG_S           gp,O32_FRAMESZ-3*SZREG(sp)
  49                 REG_S           s7,O32_FRAMESZ-4*SZREG(sp)
  50                 REG_S           s6,O32_FRAMESZ-5*SZREG(sp)
  51                 REG_S           s5,O32_FRAMESZ-6*SZREG(sp)
  52                 REG_S           s4,O32_FRAMESZ-7*SZREG(sp)
  53                 REG_S           s3,O32_FRAMESZ-8*SZREG(sp)
  54                 REG_S           s2,O32_FRAMESZ-9*SZREG(sp)
  55                 REG_S           s1,O32_FRAMESZ-10*SZREG(sp)
  56                 REG_S           s0,O32_FRAMESZ-11*SZREG(sp)
  57 
  58                 move            jp,a0
  59 
  60                 move            fp,sp
  61                 beqz            a1,0f
  62                 REG_SUBU        fp,a1,O32_NFRAMESZ
  63 0:
  64                 REG_S           sp,O32_NFRAMESZ-1*SZREG(fp)
  65 
  66                 sll             a0,a2,zero
  67                 sll             a1,a3,zero
  68                 sll             a2,a4,zero
  69                 sll             a3,a5,zero
  70                 sw              a6,4*O32_SZREG(fp)
  71                 sw              a7,5*O32_SZREG(fp)
  72 
  73                 PTR_LA          t0,O32_FRAMESZ(sp)
  74                 PTR_LA          t1,6*O32_SZREG(fp)
  75                 li              t2,O32_ARGC-6
  76 1:
  77                 lw              t3,(t0)
  78                 REG_ADDU        t0,SZREG
  79                 sw              t3,(t1)
  80                 REG_SUBU        t2,1
  81                 REG_ADDU        t1,O32_SZREG
  82                 bnez            t2,1b
  83 
  84                 move            sp,fp
  85 
  86                 jalr            jp
  87 
  88                 REG_L           sp,O32_NFRAMESZ-1*SZREG(sp)
  89 
  90                 REG_L           s0,O32_FRAMESZ-11*SZREG(sp)
  91                 REG_L           s1,O32_FRAMESZ-10*SZREG(sp)
  92                 REG_L           s2,O32_FRAMESZ-9*SZREG(sp)
  93                 REG_L           s3,O32_FRAMESZ-8*SZREG(sp)
  94                 REG_L           s4,O32_FRAMESZ-7*SZREG(sp)
  95                 REG_L           s5,O32_FRAMESZ-6*SZREG(sp)
  96                 REG_L           s6,O32_FRAMESZ-5*SZREG(sp)
  97                 REG_L           s7,O32_FRAMESZ-4*SZREG(sp)
  98                 REG_L           gp,O32_FRAMESZ-3*SZREG(sp)
  99                 REG_L           fp,O32_FRAMESZ-2*SZREG(sp)
 100                 REG_L           ra,O32_FRAMESZ-1*SZREG(sp)
 101 
 102                 REG_ADDU        sp,O32_FRAMESZ
 103                 jr              ra
 104 END(call_o32)