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# crt.asm
#       C RunTime:
#       Used for initialization of small data
#       anchors and stack for programs compiled using
#       Xilinx Gnu Tools.
#       Used for initialization of user's bss area
#       All external and static variables are initialized
 
/*      Vector map (Interrupts, Exceptions, Breakpoints)                 */
#       # 0x00 #                Jump to Start   (reset vector)
#       # 0x04 #                nop
#       # 0x08 #                Imm instr for soft exception address [Hi halfword]
#       # 0x0c #                Jump to sof Exception handler        [Lo halfword]
#       # 0x10 #                Imm instr for interrupt address      [Hi halfword]
#       # 0x14 #                Jump to interrupt handler            [Lo halfword]
#       # 0x18 #                nop - Reserved for breakpoint vector
#       # 0x1C #                nop - Reserved for breakpoint vector
#       # 0x20 #                Imm instr for hw exception address   [Hi halfword]
#       # 0x24 #                Jump instr to hw exception handler   [Lo halfword]
 
                        .globl _start
                        .align 2
                        .ent _start
_start:                 brai    _start1
_vector_sw_exception:   brai    _exception_handler
_vector_interrupt:      brai    _interrupt_handler
_vector_breakpoint:     brai    _breakpoint_handler
_vector_hw_exception:   brai    _hw_exception_handler
 
/* ------ crt starts here --------- */
 
_start1:                                /* Set the Small Data Anchors and the Stack pointer  */
        la r13, r0, _SDA_BASE_
        la r2, r0, _SDA2_BASE_
        la r1, r0, _STACK_START         # stack is at end of block-ram
 
_crtinit:                               /* clear sbss */
        addi    r6,r0,__sbss_start      /* SBSS beginning       */
        addi    r7,r0,__sbss_end        /* SBSS end             */
        rsub    r18,r6,r7               /* Compare              */
        blei    r18,.Lendsbss
.Lloopsbss:
        sw      r0,r6,r0
        addi    r6,r6,4
        rsub    r18,r6,r7
        bgti    r18,.Lloopsbss
.Lendsbss:                              /* clear bss */
        addi    r6,r0,__bss_start       /* BSS beginning        */
        addi    r7,r0,__bss_end         /* BSS end              */
        rsub    r18,r6,r7               /* Compare              */
        blei    r18,.Lendbss
.Lloopbss:
        sw      r0,r6,r0
        addi    r6,r6,4
        rsub    r18,r6,r7
        bgti    r18,.Lloopbss
.Lendbss:
 
        brlid   r15,main                # enter main program (ignoring parameters: r5, r6 & r7)
        nop                             # fall throught to exit
        .end _start
 
_exception_handler:
_interrupt_handler:
_breakpoint_handler:
_hw_exception_handler:
 
        .globl exit                     # exit library call
        .ent exit
exit:
        bri _start1
        .end exit

Line No.	Rev	Author	Line
1	3	toni32	`# crt.asm`
2			`# C RunTime:`
3			`# Used for initialization of small data`
4			`# anchors and stack for programs compiled using`
5			`# Xilinx Gnu Tools.`
6			`# Used for initialization of user's bss area`
7			`# All external and static variables are initialized`
8
9			`/* Vector map (Interrupts, Exceptions, Breakpoints) */`
10			`# # 0x00 # Jump to Start (reset vector)`
11			`# # 0x04 # nop`
12			`# # 0x08 # Imm instr for soft exception address [Hi halfword]`
13			`# # 0x0c # Jump to sof Exception handler [Lo halfword]`
14			`# # 0x10 # Imm instr for interrupt address [Hi halfword]`
15			`# # 0x14 # Jump to interrupt handler [Lo halfword]`
16			`# # 0x18 # nop - Reserved for breakpoint vector`
17			`# # 0x1C # nop - Reserved for breakpoint vector`
18			`# # 0x20 # Imm instr for hw exception address [Hi halfword]`
19			`# # 0x24 # Jump instr to hw exception handler [Lo halfword]`
20
21	4	toni32	`.globl _start`
22			`.align 2`
23			`.ent _start`
24			`_start: brai _start1`
25			`_vector_sw_exception: brai _exception_handler`
26			`_vector_interrupt: brai _interrupt_handler`
27			`_vector_breakpoint: brai _breakpoint_handler`
28			`_vector_hw_exception: brai _hw_exception_handler`
29	3	toni32
30	4	toni32	`/* ------ crt starts here --------- */`
31	3	toni32
32			`_start1: /* Set the Small Data Anchors and the Stack pointer */`
33			`la r13, r0, _SDA_BASE_`
34			`la r2, r0, _SDA2_BASE_`
35			`la r1, r0, _STACK_START # stack is at end of block-ram`
36
37			`_crtinit: /* clear sbss */`
38			`addi r6,r0,__sbss_start /* SBSS beginning */`
39			`addi r7,r0,__sbss_end /* SBSS end */`
40			`rsub r18,r6,r7 /* Compare */`
41			`blei r18,.Lendsbss`
42			`.Lloopsbss:`
43			`sw r0,r6,r0`
44			`addi r6,r6,4`
45			`rsub r18,r6,r7`
46			`bgti r18,.Lloopsbss`
47			`.Lendsbss: /* clear bss */`
48			`addi r6,r0,__bss_start /* BSS beginning */`
49			`addi r7,r0,__bss_end /* BSS end */`
50			`rsub r18,r6,r7 /* Compare */`
51			`blei r18,.Lendbss`
52			`.Lloopbss:`
53			`sw r0,r6,r0`
54			`addi r6,r6,4`
55			`rsub r18,r6,r7`
56			`bgti r18,.Lloopbss`
57			`.Lendbss:`
58
59			`brlid r15,main # enter main program (ignoring parameters: r5, r6 & r7)`
60			`nop # fall throught to exit`
61			`.end _start`
62
63	4	toni32	`_exception_handler:`
64			`_interrupt_handler:`
65			`_breakpoint_handler:`
66			`_hw_exception_handler:`
67
68	3	toni32	`.globl exit # exit library call`
69			`.ent exit`
70			`exit:`
71	4	toni32	`bri _start1`
72	3	toni32	`.end exit`

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[/] [openfire2/] [trunk/] [sw/] [crt/] [crt-bram.s] - Blame information for rev 4