Subversion Repositories openrisc_2011-10-31

/* crt0.S -- startup file for frv.
 * 
 * Copyright (c) 2002, 2003 Red Hat, Inc
 *
 * The authors hereby grant permission to use, copy, modify, distribute,
 * and license this software and its documentation for any purpose, provided
 * that existing copyright notices are retained in all copies and that this
 * notice is included verbatim in any distributions. No written agreement,
 * license, or royalty fee is required for any of the authorized uses.
 * Modifications to this software may be copyrighted by their authors
 * and need not follow the licensing terms described here, provided that
 * the new terms are clearly indicated on the first page of each file where
 * they apply.
 */

#include <frv-asm.h>

        /* statically store .Lcall's address so we can see if we are running
           at the location we were linked for or a different location.  */
        .data
        .type   EXT(__start_cmp),@object
        .size   EXT(__start_cmp),4
        .p2align 2
EXT(__start_cmp):
        .picptr  .Lcall
        
        .globl  __start
        .weak   _start
        .text
        .type   __start,@function
__start:
_start:
        call    .Lcall                          /* set up _gp in a pic-friendly manor */
.Lcall: movsg   lr, gr4
        P(sethi) #gprelhi(.Lcall), gr5
        setlo    #gprello(.Lcall), gr5
        P(sub)   gr4, gr5, gr16

#if ! __FRV_FDPIC__
        sethi    #gprelhi(EXT(_stack)), sp      /* load up stack pointer */
        P(setlo) #gprello(EXT(_stack)), sp
        setlos   #0, fp                         /* zero fp to allow unwinders to stop */
        P(add)   sp, gr16, sp

#define FDPIC(...)
#else
#define FDPIC(...) __VA_ARGS__
        
        /* The assembler will rightfully claim that
        #hi/lo(__stacksize) are unsafe for PIC, but since __stacksize
        is absolute, and we don't want it to be relocated, we should
        be fine.  */

        sethi   #gprelhi(EXT(__end)), gr6
        P(sethi) #hi(EXT(__stacksize+7)), gr5
        setlo   #gprello(EXT(__end)), gr6
        P(setlo) #lo(EXT(__stacksize+7)), gr5
        add     gr6, gr16, gr6
        add     gr6, gr5, gr5
        andi    gr5, -8, sp

        /* Using GPREL to compute _GLOBAL_OFFSET_TABLE_'s will force
        the entire program to relocate as a unit, which is fine for
        frv-elf.  */
        
        P(sethi) #gprelhi(EXT(_GLOBAL_OFFSET_TABLE_)), gr15
        setlo    #gprello(EXT(_GLOBAL_OFFSET_TABLE_)), gr15
        /* We compute the value in a call-saved register (that happens
        to be the PIC register in the EABI, and copy it to gr15 before
        every call.  */
        add      gr15, gr16, gr17
#endif

        sethi    #gprelhi(EXT(__start_cmp)), gr5
        setlo    #gprello(EXT(__start_cmp)), gr5
        ld       @(gr5,gr16), gr6
        subcc   gr4, gr6, gr8, icc0
        beq     icc0, 0, .Lfixed

        P(st)   gr4, @(gr5, gr16)       /* update so if we restart no need to fixup */
        setlos  4, gr11

#if ! __FRV_FDPIC__

                                        /* fixup the .ctors list */
        sethi    #gprelhi(EXT(__CTOR_LIST__)), gr9
        P(sethi) #gprelhi(EXT(__CTOR_END__)), gr10
        setlo    #gprello(EXT(__CTOR_LIST__)), gr9
        P(setlo) #gprello(EXT(__CTOR_END__)), gr10
        add      gr9, gr16, gr9
        P(add)   gr10, gr16, gr10
        addi     gr9, 4, gr9
        P(subi)  gr10, 4, gr10
        call     EXT(__frv_fixptrs)

                                        /* fixup the .dtors list */
        P(sethi) #gprelhi(EXT(__DTOR_LIST__)), gr9
        sethi    #gprelhi(EXT(__DTOR_END__)), gr10
        P(setlo) #gprello(EXT(__DTOR_LIST__)), gr9
        setlo    #gprello(EXT(__DTOR_END__)), gr10
        P(add)   gr9, gr16, gr9
        add      gr10, gr16, gr10
        P(addi)  gr9, 4, gr9
        subi     gr10, 4, gr10
        call     EXT(__frv_fixptrs)
#endif /* ! __FRV_FDPIC__ */

                                        /* fixup the user .rofixup list */
        P(sethi) #gprelhi(EXT(__ROFIXUP_LIST__)), gr9
        sethi    #gprelhi(EXT(__ROFIXUP_END__)), gr10
        P(setlo) #gprello(EXT(__ROFIXUP_LIST__)), gr9
        setlo    #gprello(EXT(__ROFIXUP_END__)), gr10
        P(add)   gr9, gr16, gr9
        add      gr10, gr16, gr10
        FDPIC(mov gr17, gr15)
        call     EXT(__frv_fix_usrptrs)

.Lfixed:

/* HSR flags */
#define HSR_ICE  0x80000000             /* Instruction cache enable */
#define HSR_DCE  0x40000000             /* Data cache enable */
#define HSR_CBM  0x08000000             /* Cache copy back mode */
#define HSR_EIMM 0x04000000             /* Enable Instruction MMU */
#define HSR_EDMM 0x02000000             /* Enable Data MMU */
#define HSR_EMEM 0x00800000             /* Enable MMU miss exception mask */
#define HSR_RME  0x00400000             /* Ram mode enable */
#define HSR_SA   0x00001000             /* Start address */
#define HSR_FRN  0x00000800             /* Number of FPRs */
#define HSR_GRN  0x00000400             /* Number of GPRs */
#define HSR_FRHE 0x00000200             /* FR Higher Enable */
#define HSR_FRLE 0x00000100             /* FR Lower Enable */
#define HSR_GRHE 0x00000080             /* GR Higher Enable */
#define HSR_GRLE 0x00000040             /* GR Lower Enable */

#ifndef HSR_CLEAR
#define HSR_CLEAR 0
#endif

#ifndef HSR_SET
#ifndef FRV_NO_CACHE
#define HSR_SET (HSR_ICE|HSR_DCE|HSR_FRHE|HSR_FRLE|HSR_GRHE|HSR_GRLE)
#else
#define HSR_SET (HSR_FRHE|HSR_FRLE|HSR_GRHE|HSR_GRLE)
#endif
#endif

/* PSR flags */
#define PSR_ICE  0x00010000             /* In circuit emulation mode */
#define PSR_NEM  0x00004000             /* Non-exception mode */
#define PSR_CM   0x00002000             /* Conditional mode */
#define PSR_BE   0x00001000             /* Big endian mode */
#define PSR_EF   0x00000100             /* Enable floating point */
#define PSR_EM   0x00000080             /* Enable media instructions */
#define PSR_S    0x00000004             /* Enable supervisor mode */
#define PSR_PS   0x00000002             /* Previous supervisor mode */
#define PSR_ET   0x00000001             /* Enable interrupts */

#ifndef PSR_CLEAR
#if __FRV_FPR__
#define PSR_CLEAR 0
#else
#define PSR_CLEAR (PSR_EF|PSR_EM)
#endif
#endif

#ifndef PSR_SET
#if __FRV_FPR__
#define PSR_SET (PSR_NEM|PSR_CM|PSR_EF|PSR_EM)
#else
#define PSR_SET (PSR_NEM|PSR_CM)
#endif
#endif

        /* Enable floating point */
        movsg     hsr0, gr4
        P(sethi)  #hi(HSR_SET), gr5
        setlo     #lo(HSR_SET), gr5
        P(sethi)  #hi(~HSR_CLEAR), gr6
        setlo     #lo(~HSR_CLEAR), gr6
        or        gr4, gr5, gr4
        and       gr4, gr6, gr4
        movgs     gr4, hsr0

        movsg     psr, gr4
        P(sethi)  #hi(PSR_SET), gr5
        setlo     #lo(PSR_SET), gr5
        P(sethi)  #hi(~PSR_CLEAR), gr6
        setlo     #lo(~PSR_CLEAR), gr6
        or        gr4, gr5, gr4
        and       gr4, gr6, gr4
        movgs     gr4, psr

        /* zero the bss area */
        P(sethi)  #gprelhi(__bss_start), gr8
        sethi     #gprelhi(__end), gr4
        P(setlo)  #gprello(__bss_start), gr8
        setlo     #gprello(__end), gr4
        P(add)    gr8, gr16, gr8
        add       gr4, gr16, gr4
        P(setlos) #0, gr9
        sub       gr4, gr8, gr10
        FDPIC(mov gr17, gr15)
        call      EXT(memset)

        P(setlos) #0, gr8               /* zero argc, argv, envp */
        setlos    #0, gr9
        P(setlos) #0, gr10

        FDPIC(mov gr17, gr15)
        call      EXT(main)
        FDPIC(mov gr17, gr15)
        call      EXT(exit)
.Lend:
        .size   __start,(.Lend-__start)

#if ! __FRV_FDPIC__
        /* Routine to adjust pointers
           gr8  = difference to adjust by
           gr9  = starting address
           gr10 = ending address + 4
           gr11 = amount to add to the pointer each iteration.  */
        .globl  EXT(__frv_fixptrs)
        .type   EXT(__frv_fixptrs),@function
EXT(__frv_fixptrs):
        P(sub)  gr9, gr11, gr9
        sub     gr10, gr11, gr10
.Lloop2:
        cmp     gr10, gr9, icc0
        bls     icc0, 0, .Lret2

        ldu     @(gr9,gr11), gr5
        add     gr8, gr5, gr5
        P(st)   gr5, @(gr9,gr0)
        bra     .Lloop2

.Lret2: ret
.Lend2:
        .size   EXT(__frv_fixptrs),.Lend2-EXT(__frv_fixptrs)
#endif /* ! __FRV_FDPIC__ */

        /* Routine to adjust statically initialized pointers
           Note since these are pointers to pointers, they
           need to be adjusted themsevles.

           gr8  = difference to adjust by
           gr9  = starting address
           gr10 = ending address + 4
           gr11 = amount to add to the pointer each iteration.  */
        .globl  EXT(__frv_fix_usrptrs)
        .type   EXT(__frv_fix_usrptrs),@function
EXT(__frv_fix_usrptrs):
        P(sub)  gr9, gr11, gr9
        sub     gr10, gr11, gr10
.Lloop3:
        cmp     gr10, gr9, icc0
        bls     icc0, 0, .Lret3

        ldu     @(gr9,gr11), gr5
        ld      @(gr5, gr8), gr6
        cmp     gr6, gr0, icc0          /* skip pointers initialized to 0 */
        beq     icc0, 0, .Lloop3

        add     gr8, gr6, gr6
        P(st)   gr6, @(gr5,gr8)
        bra     .Lloop3

.Lret3: ret
.Lend3:
        .size   EXT(__frv_fix_usrptrs),.Lend2-EXT(__frv_fix_usrptrs)

        .section .data
        .global __dso_handle
        .weak __dso_handle
__dso_handle:
        .long   0