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[/] [or1k/] [trunk/] [newlib/] [newlib/] [libc/] [sys/] [arm/] [crt0.S] - Blame information for rev 1774

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1 39 lampret
#include "swi.h"
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/* ANSI concatenation macros.  */
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#define CONCAT(a, b) CONCAT2(a, b)
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#define CONCAT2(a, b) a ## b
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#ifdef __USER_LABEL_PREFIX__
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#define FUNCTION( name ) CONCAT (__USER_LABEL_PREFIX__, name)
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#else
10 56 joel
#error __USER_LABEL_PREFIX is not defined
11 39 lampret
#endif
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/* .text is used instead of .section .text so it works with arm-aout too.  */
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        .text
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        .code 32
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        .align  0
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        .global _mainCRTStartup
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        .global _start
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        .global start
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start:
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_start:
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_mainCRTStartup:
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/* Start by setting up a stack */
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#ifdef ARM_RDP_MONITOR
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        /*  Issue Demon SWI to read stack info */
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        swi     SWI_GetEnv      /*  Returns command line in r0 */
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        mov     sp,r1           /*  and the highest memory address in r1 */
30 56 joel
        ldr     sl, .LC2        /*  stack limit is at end of data */
31 39 lampret
        add     sl, sl, #256    /*  allow slop for stack overflow handling */
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                                /*  and small frames */
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#else
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#ifdef ARM_RDI_MONITOR
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        /*  Issue Angel SWI to read stack info */
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        mov     r0, #AngelSWI_Reason_HeapInfo
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        adr     r1, .LC0        /*  point at ptr to 4 words to receive data */
38 39 lampret
        swi     AngelSWI_ARM    /*  We are always in ARM mode for startup */
39 56 joel
        ldr     r0, .LC0        /*  point at values read */
40 39 lampret
        ldr     sp, [r0, #8]
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        ldr     sl, [r0, #12]
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        add     sl, sl, #256    /*  allow slop for stack overflow handling */
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                                /*  and small frames */
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#else
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        /*  Set up the stack pointer to a fixed value */
46 56 joel
        ldr     r3, .LC0
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        mov     sp, r3
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        /* Setup a default stack-limit in-case the code has been
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           compiled with "-mapcs-stack-check".  Hard-wiring this value
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           is not ideal, since there is currently no support for
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           checking that the heap and stack have not collided, or that
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           this default 64k is enough for the program being executed.
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           However, it ensures that this simple crt0 world will not
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           immediately cause an overflow event:  */
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        sub     sl, sp, #64 << 10       /* Still assumes 256bytes below sl */
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#endif
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#endif
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        mov     a2, #0                  /* Second arg: fill value */
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        mov     fp, a2                  /* Null frame pointer */
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        mov     r7, a2                  /* Null frame pointer for Thumb */
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62 56 joel
        ldr     a1, .LC1                /* First arg: start of memory block */
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        ldr     a3, .LC2
64 39 lampret
        sub     a3, a3, a1              /* Third arg: length of block */
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#ifdef __thumb__                /* Enter Thumb mode.... */
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        add     a4, pc, #1      /* Get the address of the Thumb block */
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        bx      a4              /* Go there and start Thumb decoding  */
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        .code 16
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        .global __change_mode
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        .thumb_func
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__change_mode:
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#endif
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        bl      FUNCTION (memset)
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#if !defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR)
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        mov     r0, #0          /*  no arguments  */
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        mov     r1, #0          /*  no argv either */
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#else
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        /* Need to set up standard file handles */
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        bl      FUNCTION (initialise_monitor_handles)
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#ifdef ARM_RDP_MONITOR
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        swi     SWI_GetEnv      /*  sets r0 to point to the command line */
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        mov     r1, r0
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#else
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        mov     r0, #AngelSWI_Reason_GetCmdLine
91 56 joel
        adr     r1, .LC30       /*  Space for command line */
92 39 lampret
        swi     AngelSWI
93 56 joel
        ldr     r1, .LC30
94 39 lampret
#endif
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        /*  Parse string at r1 */
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        mov     r0, #0          /*  count of arguments so far */
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.LC10:
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/*  Skip leading blanks */
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#ifdef __thumb__
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        ldrb    r3, [r1]
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        add     r1, #1
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#else
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        ldrb    r3, [r1], #1
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#endif
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        cmp     r3, #0
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        beq     .LC12
107 39 lampret
        cmp     r3, #' '
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        beq     .LC10
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/*  See whether we are scanning a string */
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        cmp     r3, #'"'
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#ifdef __thumb__
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        beq     .LC20
114 39 lampret
        cmp     r3, #'\''
115 56 joel
        bne     .LC21
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.LC20:
117 39 lampret
        mov     r2, r3
118 56 joel
        b       .LC22
119 39 lampret
 
120 56 joel
.LC21:
121 39 lampret
        mov     r2, #' '        /*  terminator type */
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        sub     r1, r1, #1      /*  adjust back to point at start char */
123 56 joel
.LC22:
124 39 lampret
#else
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        cmpne   r3, #'\''
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        moveq   r2, r3
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        movne   r2, #' '        /*  terminator type */
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        subne   r1, r1, #1      /*  adjust back to point at start char */
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#endif
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131
/*  Stack a pointer to the current argument */
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#ifdef __thumb__
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        push    {r1}
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#else
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        stmfd   sp!, {r1}
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#endif
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        add     r0, r0, #1
138 56 joel
.LC11:
139 39 lampret
#ifdef __thumb__
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        ldrb    r3, [r1]
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        add     r1, #1
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#else
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        ldrb    r3, [r1], #1
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#endif
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        cmp     r3, #0
146 56 joel
        beq     .LC12
147 39 lampret
        cmp     r2, r3          /*  reached terminator? */
148 56 joel
        bne     .LC11
149 39 lampret
        mov     r2, #0
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        sub     r3, r1, #1
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        strb    r2, [r3]        /*  terminate the arg string */
152 56 joel
        b       .LC10
153 39 lampret
 
154 56 joel
.LC12:
155 39 lampret
        mov     r1, sp          /*  point at stacked arg pointers */
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        /* We've now got the stacked args in order reverse the */
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#ifdef __thumb__
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        mov     r2, r0
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        lsl     r2, #2
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        add     r2, sp
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        mov     r3, sp
162 56 joel
.LC15:  cmp     r2, r3
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        bls     .LC14
164 39 lampret
        sub     r2, #4
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        ldr     r4, [r2]
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        ldr     r5, [r3]
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        str     r5, [r2]
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        str     r4, [r3]
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        add     r3, #4
170 56 joel
        b       .LC15
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.LC14:
172 39 lampret
#else
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        add     r2, sp, r0, LSL #2      /* End of args */
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        mov     r3, sp                  /* Start of args */
175 56 joel
.LC13:  cmp     r2, r3
176 39 lampret
        ldrhi   r4,[r2, #-4]            /* Reverse ends of list */
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        ldrhi   r5, [r3]
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        strhi   r5, [r2, #-4]!
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        strhi   r4, [r3], #4
180 56 joel
        bhi     .LC13
181 39 lampret
#endif
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183
#endif
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        bl      FUNCTION (main)
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        bl      FUNCTION (exit)         /* Should not return */
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188
#ifdef __thumb__
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        /* Come out of Thumb mode... This code should be redundant...   */
190
 
191
        mov     a4, pc
192
        bx      a4
193
 
194
        .code 32
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        .global change_back
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change_back:
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        /* Halt the execution.  This code should never be executed.  */
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        /*
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        ** With no debug monitor, this probably aborts (eventually).
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        ** With a Demon debug monitor, this halts cleanly.
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        ** With an Angel debug monitor, this will report 'Unknown SWI'.
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        */
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        swi     SWI_Exit
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#endif
205
 
206
        /* For Thumb, constants must be after the code since only
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        positive offsets are supported for PC relative addresses. */
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209
        .align 0
210 56 joel
.LC0:
211 39 lampret
#ifdef ARM_RDI_MONITOR
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        .word   HeapBase
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#else
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#ifndef ARM_RDP_MONITOR
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#ifdef __pe__
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        .word   0x800000
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#else
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/*      .word   0x80000 */              /* Top of RAM on the PIE board */
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#endif
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#endif
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#endif
222 56 joel
.LC1:
223 39 lampret
        .word   __bss_start__
224 56 joel
.LC2:
225 39 lampret
        .word   __bss_end__
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227
#ifdef ARM_RDI_MONITOR
228 56 joel
.LC30:  .word   CommandLine
229 39 lampret
 
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/*  Workspace for Angel calls. */
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        .data
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/*  Data returned by monitor SWI */
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HeapBase:       .word   0
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HeapLimit:      .word   0
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StackBase:      .word   0
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StackLimit:     .word   0
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CommandLine:    .space  256,0   /*  Maximum length of 255 chars handled */
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#endif
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#ifdef __pe__
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        .section .idata$3
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        .long   0,0,0,0,0,0,0,0
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#endif
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