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/*
 * crt0.S -- startup file for MIPS.
 *
 * Copyright (c) 1995, 1996, 1997, 2001 Cygnus Support
 *
 * 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.
 */
 
#ifdef __mips16
/* This file contains 32 bit assembly code.  */
        .set nomips16
#endif
 
#include "regs.S"
 
/*
 * Set up some room for a stack. We just grab a chunk of memory.
 */
#define STACK_SIZE  0x4000
#define GLOBAL_SIZE 0x2000
 
#define STARTUP_STACK_SIZE      0x0100
 
/* This is for referencing addresses that are not in the .sdata or
   .sbss section under embedded-pic, or before we've set up gp.  */
#ifdef __mips_embedded_pic
# ifdef __mips64
#  define LA(t,x) la t,x-PICBASE ; daddu t,s0,t
# else
#  define LA(t,x) la t,x-PICBASE ; addu t,s0,t
# endif
#else /* __mips_embedded_pic */
# define LA(t,x) la t,x
#endif /* __mips_embedded_pic */
 
        .comm   __memsize, 12
        .comm   __lstack, STARTUP_STACK_SIZE
 
        .text
        .align  2
 
/* Without the following nop, GDB thinks _start is a data variable.
 * This is probably a bug in GDB in handling a symbol that is at the
 * start of the .text section.
 */
        nop
 
        .globl  hardware_hazard_hook .text
        .globl  _start
        .ent    _start
_start:
        .set    noreorder
#ifdef __mips_embedded_pic
#define PICBASE start_PICBASE
        PICBASE = .+8
        bal     PICBASE
        nop
        move    s0,$31
#endif
#if __mips<3
#  define STATUS_MASK (SR_CU1|SR_PE)
#else
/* Post-mips2 has no SR_PE bit.  */
#  ifdef __mips64
/* Turn on 64-bit addressing and additional float regs.  */
#    define STATUS_MASK (SR_CU1|SR_FR|SR_KX|SR_SX|SR_UX)
#  else
#    if __mips_fpr==32
#      define STATUS_MASK (SR_CU1)
#    else
/* Turn on additional float regs.  */
#      define STATUS_MASK (SR_CU1|SR_FR)
#    endif
#  endif
#endif
        li      v0, STATUS_MASK
        mtc0    v0, C0_SR
        mtc0    zero, C0_CAUSE
        nop
 
        /* Avoid hazard from FPU enable and other SR changes.  */
        LA (t0, hardware_hazard_hook)
        beq     t0,zero,1f
        nop
        jal     t0
        nop
1:
 
/* Check for FPU presence.  Don't check if we know that soft_float is
   being used.  (This also avoids illegal instruction exceptions.)  */
 
#ifndef __mips_soft_float
        li      t2,0xAAAA5555
        mtc1    t2,fp0          /* write to FPR 0 */
        mtc1    zero,fp1        /* write to FPR 1 */
        mfc1    t0,fp0
        mfc1    t1,fp1
        nop
        bne     t0,t2,1f        /* check for match */
        nop
        bne     t1,zero,1f      /* double check */
        nop
        j       2f              /* FPU is present. */
        nop
#endif
1:
        /* FPU is not present.  Set status register to say that. */
        li      v0, (STATUS_MASK-(STATUS_MASK & SR_CU1))
        mtc0    v0, C0_SR
        nop
        /* Avoid hazard from FPU disable.  */
        LA (t0, hardware_hazard_hook)
        beq     t0,zero,2f
        nop
        jal     t0
        nop
2:
 
 
/* Fix high bits, if any, of the PC so that exception handling
   doesn't get confused.  */
        LA (v0, 3f)
        jr      v0
        nop
3:
        LA (gp, _gp)                            # set the global data pointer
        .end _start
 
/*
 * zero out the bss section.
 */
        .globl  __memsize
        .globl  get_mem_info .text
        .globl  __stack
        .globl  __global
        .ent    zerobss
zerobss:
        LA (v0, _fbss)
        LA (v1, _end)
3:
        sw      zero,0(v0)
        bltu    v0,v1,3b
        addiu   v0,v0,4                         # executed in delay slot
 
        la      t0, __lstack                    # make a small stack so we
        addiu   sp, t0, STARTUP_STACK_SIZE      # can run some C code
        la      a0, __memsize                   # get the usable memory size
        jal     get_mem_info
        nop
 
        /* setup the stack pointer */
        LA (t0, __stack)                        # is __stack set ?
        bne     t0,zero,4f
        nop
 
        /* NOTE: a0[0] contains the amount of memory available, and
                 not the last memory address. */
        la      a0, __memsize
        lw      t0,0(a0)                        # last address of memory available
        la      t1,K0BASE                       # cached kernel memory
        addu    t0,t0,t1                        # get the end of memory address
        /* Allocate 32 bytes for the register parameters.  Allocate 16
           bytes for a null argv and envp.  Round the result up to 64
           bytes to preserve alignment.  */
        subu    t0,t0,64
4:
        move    sp,t0                           # set stack pointer
        .end    zerobss
 
/*
 * initialize target specific stuff. Only execute these
 * functions it they exist.
 */
        .globl  hardware_init_hook .text
        .globl  software_init_hook .text
        .type   _fini,@function
        .type   _init,@function
        .globl  atexit .text
        .globl  exit .text
        .ent    init
init:
        LA (t9, hardware_init_hook)             # init the hardware if needed
        beq     t9,zero,6f
        nop
        jal     t9
        nop
6:
        LA (t9, software_init_hook)             # init the hardware if needed
        beq     t9,zero,7f
        nop
        jal     t9
        nop
7:
        LA (a0, _fini)
        jal     atexit
        nop
 
#ifdef GCRT0
        .globl  _ftext
        .globl  _extext
        LA (a0, _ftext)
        LA (a1, _etext)
        jal     monstartup
        nop
#endif
 
 
        jal     _init                           # run global constructors
        nop
 
        addiu   a1,sp,32                        # argv = sp + 32
        addiu   a2,sp,40                        # envp = sp + 40
#if __mips64
        sd      zero,(a1)                       # argv[argc] = 0
        sd      zero,(a2)                       # envp[0] = 0
#else
        sw      zero,(a1)
        sw      zero,(a2)
#endif
        jal     main                            # call the program start function
        move    a0,zero                         # set argc to 0
 
        # fall through to the "exit" routine
        jal     exit                            # call libc exit to run the G++
                                                # destructors
        move    a0,v0                           # pass through the exit code
        .end    init
 
 
/* Assume the PICBASE set up above is no longer valid below here.  */
#ifdef __mips_embedded_pic
#undef PICBASE
#endif
 
/*
 * _exit -- Exit from the application. Normally we cause a user trap
 *          to return to the ROM monitor for another run. NOTE: This is
 *          the only other routine we provide in the crt0.o object, since
 *          it may be tied to the "_start" routine. It also allows
 *          executables that contain a complete world to be linked with
 *          just the crt0.o object.
 */
        .globl  hardware_exit_hook .text
        .globl  _exit
        .ent _exit
_exit:
7:
#ifdef __mips_embedded_pic
        /* Need to reinit PICBASE, since we might be called via exit()
           rather than via a return path which would restore old s0.  */
#define PICBASE exit_PICBASE
        PICBASE = .+8
        bal     PICBASE
        nop
        move    s0,$31
#endif
#ifdef GCRT0
        LA (t0, _mcleanup)
        jal     t0
        nop
#endif
        LA (t0, hardware_exit_hook)
        beq     t0,zero,1f
        nop
        jal     t0
        nop
1:
 
        # break instruction can cope with 0xfffff, but GAS limits the range:
        break   1023
        b       7b                              # but loop back just in-case
        nop
        .end _exit
 
/* Assume the PICBASE set up above is no longer valid below here.  */
#ifdef __mips_embedded_pic
#undef PICBASE
#endif
 
/* EOF crt0.S */

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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [libgloss/] [mips/] [crt0.S] - Blame information for rev 455

Line No.	Rev	Author	Line
1	148	jeremybenn	`/*`
2			`* crt0.S -- startup file for MIPS.`
3			`*`
4			`* Copyright (c) 1995, 1996, 1997, 2001 Cygnus Support`
5			`*`
6			`* The authors hereby grant permission to use, copy, modify, distribute,`
7			`* and license this software and its documentation for any purpose, provided`
8			`* that existing copyright notices are retained in all copies and that this`
9			`* notice is included verbatim in any distributions. No written agreement,`
10			`* license, or royalty fee is required for any of the authorized uses.`
11			`* Modifications to this software may be copyrighted by their authors`
12			`* and need not follow the licensing terms described here, provided that`
13			`* the new terms are clearly indicated on the first page of each file where`
14			`* they apply.`
15			`*/`
16
17			`#ifdef __mips16`
18			`/* This file contains 32 bit assembly code. */`
19			`.set nomips16`
20			`#endif`
21
22			`#include "regs.S"`
23
24			`/*`
25			`* Set up some room for a stack. We just grab a chunk of memory.`
26			`*/`
27			`#define STACK_SIZE 0x4000`
28			`#define GLOBAL_SIZE 0x2000`
29
30			`#define STARTUP_STACK_SIZE 0x0100`
31
32			`/* This is for referencing addresses that are not in the .sdata or`
33			`.sbss section under embedded-pic, or before we've set up gp. */`
34			`#ifdef __mips_embedded_pic`
35			`# ifdef __mips64`
36			`# define LA(t,x) la t,x-PICBASE ; daddu t,s0,t`
37			`# else`
38			`# define LA(t,x) la t,x-PICBASE ; addu t,s0,t`
39			`# endif`
40			`#else /* __mips_embedded_pic */`
41			`# define LA(t,x) la t,x`
42			`#endif /* __mips_embedded_pic */`
43
44			`.comm __memsize, 12`
45			`.comm __lstack, STARTUP_STACK_SIZE`
46
47			`.text`
48			`.align 2`
49
50			`/* Without the following nop, GDB thinks _start is a data variable.`
51			`* This is probably a bug in GDB in handling a symbol that is at the`
52			`* start of the .text section.`
53			`*/`
54			`nop`
55
56			`.globl hardware_hazard_hook .text`
57			`.globl _start`
58			`.ent _start`
59			`_start:`
60			`.set noreorder`
61			`#ifdef __mips_embedded_pic`
62			`#define PICBASE start_PICBASE`
63			`PICBASE = .+8`
64			`bal PICBASE`
65			`nop`
66			`move s0,$31`
67			`#endif`
68			`#if __mips<3`
69			`# define STATUS_MASK (SR_CU1\|SR_PE)`
70			`#else`
71			`/* Post-mips2 has no SR_PE bit. */`
72			`# ifdef __mips64`
73			`/* Turn on 64-bit addressing and additional float regs. */`
74			`# define STATUS_MASK (SR_CU1\|SR_FR\|SR_KX\|SR_SX\|SR_UX)`
75			`# else`
76			`# if __mips_fpr==32`
77			`# define STATUS_MASK (SR_CU1)`
78			`# else`
79			`/* Turn on additional float regs. */`
80			`# define STATUS_MASK (SR_CU1\|SR_FR)`
81			`# endif`
82			`# endif`
83			`#endif`
84			`li v0, STATUS_MASK`
85			`mtc0 v0, C0_SR`
86			`mtc0 zero, C0_CAUSE`
87			`nop`
88
89			`/* Avoid hazard from FPU enable and other SR changes. */`
90			`LA (t0, hardware_hazard_hook)`
91			`beq t0,zero,1f`
92			`nop`
93			`jal t0`
94			`nop`
95			`1:`
96
97			`/* Check for FPU presence. Don't check if we know that soft_float is`
98			`being used. (This also avoids illegal instruction exceptions.) */`
99
100			`#ifndef __mips_soft_float`
101			`li t2,0xAAAA5555`
102			`mtc1 t2,fp0 /* write to FPR 0 */`
103			`mtc1 zero,fp1 /* write to FPR 1 */`
104			`mfc1 t0,fp0`
105			`mfc1 t1,fp1`
106			`nop`
107			`bne t0,t2,1f /* check for match */`
108			`nop`
109			`bne t1,zero,1f /* double check */`
110			`nop`
111			`j 2f /* FPU is present. */`
112			`nop`
113			`#endif`
114			`1:`
115			`/* FPU is not present. Set status register to say that. */`
116			`li v0, (STATUS_MASK-(STATUS_MASK & SR_CU1))`
117			`mtc0 v0, C0_SR`
118			`nop`
119			`/* Avoid hazard from FPU disable. */`
120			`LA (t0, hardware_hazard_hook)`
121			`beq t0,zero,2f`
122			`nop`
123			`jal t0`
124			`nop`
125			`2:`
126
127
128			`/* Fix high bits, if any, of the PC so that exception handling`
129			`doesn't get confused. */`
130			`LA (v0, 3f)`
131			`jr v0`
132			`nop`
133			`3:`
134			`LA (gp, _gp) # set the global data pointer`
135			`.end _start`
136
137			`/*`
138			`* zero out the bss section.`
139			`*/`
140			`.globl __memsize`
141			`.globl get_mem_info .text`
142			`.globl __stack`
143			`.globl __global`
144			`.ent zerobss`
145			`zerobss:`
146			`LA (v0, _fbss)`
147			`LA (v1, _end)`
148			`3:`
149			`sw zero,0(v0)`
150			`bltu v0,v1,3b`
151			`addiu v0,v0,4 # executed in delay slot`
152
153			`la t0, __lstack # make a small stack so we`
154			`addiu sp, t0, STARTUP_STACK_SIZE # can run some C code`
155			`la a0, __memsize # get the usable memory size`
156			`jal get_mem_info`
157			`nop`
158
159			`/* setup the stack pointer */`
160			`LA (t0, __stack) # is __stack set ?`
161			`bne t0,zero,4f`
162			`nop`
163
164			`/* NOTE: a0[0] contains the amount of memory available, and`
165			`not the last memory address. */`
166			`la a0, __memsize`
167			`lw t0,0(a0) # last address of memory available`
168			`la t1,K0BASE # cached kernel memory`
169			`addu t0,t0,t1 # get the end of memory address`
170			`/* Allocate 32 bytes for the register parameters. Allocate 16`
171			`bytes for a null argv and envp. Round the result up to 64`
172			`bytes to preserve alignment. */`
173			`subu t0,t0,64`
174			`4:`
175			`move sp,t0 # set stack pointer`
176			`.end zerobss`
177
178			`/*`
179			`* initialize target specific stuff. Only execute these`
180			`* functions it they exist.`
181			`*/`
182			`.globl hardware_init_hook .text`
183			`.globl software_init_hook .text`
184			`.type _fini,@function`
185			`.type _init,@function`
186			`.globl atexit .text`
187			`.globl exit .text`
188			`.ent init`
189			`init:`
190			`LA (t9, hardware_init_hook) # init the hardware if needed`
191			`beq t9,zero,6f`
192			`nop`
193			`jal t9`
194			`nop`
195			`6:`
196			`LA (t9, software_init_hook) # init the hardware if needed`
197			`beq t9,zero,7f`
198			`nop`
199			`jal t9`
200			`nop`
201			`7:`
202			`LA (a0, _fini)`
203			`jal atexit`
204			`nop`
205
206			`#ifdef GCRT0`
207			`.globl _ftext`
208			`.globl _extext`
209			`LA (a0, _ftext)`
210			`LA (a1, _etext)`
211			`jal monstartup`
212			`nop`
213			`#endif`
214
215
216			`jal _init # run global constructors`
217			`nop`
218
219			`addiu a1,sp,32 # argv = sp + 32`
220			`addiu a2,sp,40 # envp = sp + 40`
221			`#if __mips64`
222			`sd zero,(a1) # argv[argc] = 0`
223			`sd zero,(a2) # envp[0] = 0`
224			`#else`
225			`sw zero,(a1)`
226			`sw zero,(a2)`
227			`#endif`
228			`jal main # call the program start function`
229			`move a0,zero # set argc to 0`
230
231			`# fall through to the "exit" routine`
232			`jal exit # call libc exit to run the G++`
233			`# destructors`
234			`move a0,v0 # pass through the exit code`
235			`.end init`
236
237
238			`/* Assume the PICBASE set up above is no longer valid below here. */`
239			`#ifdef __mips_embedded_pic`
240			`#undef PICBASE`
241			`#endif`
242
243			`/*`
244			`* _exit -- Exit from the application. Normally we cause a user trap`
245			`* to return to the ROM monitor for another run. NOTE: This is`
246			`* the only other routine we provide in the crt0.o object, since`
247			`* it may be tied to the "_start" routine. It also allows`
248			`* executables that contain a complete world to be linked with`
249			`* just the crt0.o object.`
250			`*/`
251			`.globl hardware_exit_hook .text`
252			`.globl _exit`
253			`.ent _exit`
254			`_exit:`
255			`7:`
256			`#ifdef __mips_embedded_pic`
257			`/* Need to reinit PICBASE, since we might be called via exit()`
258			`rather than via a return path which would restore old s0. */`
259			`#define PICBASE exit_PICBASE`
260			`PICBASE = .+8`
261			`bal PICBASE`
262			`nop`
263			`move s0,$31`
264			`#endif`
265			`#ifdef GCRT0`
266			`LA (t0, _mcleanup)`
267			`jal t0`
268			`nop`
269			`#endif`
270			`LA (t0, hardware_exit_hook)`
271			`beq t0,zero,1f`
272			`nop`
273			`jal t0`
274			`nop`
275			`1:`
276
277			`# break instruction can cope with 0xfffff, but GAS limits the range:`
278			`break 1023`
279			`b 7b # but loop back just in-case`
280			`nop`
281			`.end _exit`
282
283			`/* Assume the PICBASE set up above is no longer valid below here. */`
284			`#ifdef __mips_embedded_pic`
285			`#undef PICBASE`
286			`#endif`
287
288			`/* EOF crt0.S */`