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; crt0_2.s - Startup code for the mrisc1. This code initializes the C
; run-time model.
;
; 12Nov01 (DJK) - The return code from main was not being passed to exit().
; Now it is passed as a parameter in R1.
;
; 10Sep01 (DJK) - The function exit() does not return. However, in the
; the case of device error (if the halt bit does not
; function properly, for instance), then a catch loop
; has been added.
;
;
; Copyright 2001, 2002, 2003, 2004 Morpho Technologies, Inc.
;
; Create a label for the start of the eh_frame section.
.section .eh_frame
__eh_frame_begin:
.equ HALT_REG, 0x300
.section .text
.global _start
_start:
;; Initialize the stack pointer
ldui sp, #%hi16(__stack)
addui sp, sp, #%lo16(__stack)
or fp, sp, sp
;; Copy data from ROM to Frame Buffer (on-chip memory)
ldui r9, #%hi16(_fbdata_start)
ori r9, r9, #%lo16(_fbdata_start)
ldui r10, #%hi16(_fbdata_end)
ori r10, r10, #%lo16(_fbdata_end)
ldui r11, #%hi16(__FRAME_BUFFER_START)
brle r10, r9, .Lnext1
ori r11, r11, #%lo16(__FRAME_BUFFER_START)
.Lcpy0:
ldw r5, r9, #$0
addi r9, r9, #$4
stw r5, r11, #$0
brlt r9, r10, .Lcpy0
addi r11, r11, #$4
.Lnext1:
;; Copy data from ROM to External Memory (off-chip memory)
ldui r9, #%hi16(_extdata_start)
ori r9, r9, #%lo16(_extdata_start)
ldui r10, #%hi16(_extdata_end)
ori r10, r10, #%lo16(_extdata_end)
ldui r11, #%hi16(__EXTERNAL_MEMORY_START)
brle r10, r9, .Lnext2
ori r11, r11, #%lo16(__EXTERNAL_MEMORY_START)
.Lcpy1:
ldw r5, r9, #$0
addi r9, r9, #$4
stw r5, r11, #$0
brlt r9, r10, .Lcpy1
addi r11, r11, #$4
.Lnext2:
;; Zero the bss space
ldui r9, #%hi16(__bss_start)
addui r9, r9, #%lo16(__bss_start)
ldui r10, #%hi16(__bss_end)
addui r10, r10, #%lo16(__bss_end)
or r0, r0, r0
brle r10, r9, .Lnext3
or r0, r0, r0
.Lcpy2:
stw r0, r9, #0
addi r9, r9, #4
or r0, r0, r0 ; nop
brle r9, r10, .Lcpy2
or r0, r0, r0 ; nop
.Lnext3:
;; Zero the external memory bss section
ldui r9, #%hi16(_extbss_start)
ori r9, r9, #%lo16(_extbss_start)
ldui r10, #%hi16(_extbss_end)
ori r10, r10, #%lo16(_extbss_end)
or r0, r0, r0
brle r10, r9, .Lnext4
or r0, r0, r0
.Lcpy3:
stw r0, r9, #$0
addi r9, r9, #$4
or r0, r0, r0
brle r9, r10, .Lcpy3
or r0, r0, r0
.Lnext4:
;; Call global and static constructors
ldui r10, #%hi16(_init)
ori r10, r10, #%lo16(_init)
or r0, r0, r0 ; nop
jal r14, r10
or r0, r0, r0 ; nop
;; Setup destructors to be called from exit.
;; (Just in case main never returns....)
ldui r10, #%hi16(atexit)
ori r10, r10, #%lo16(atexit)
ldui r1, #%hi16(_fini)
ori r1, r1, #%lo16(_fini)
or r0, r0, r0 ; nop
jal r14, r10
or r0, r0, r0 ; nop
;; Initialise argc, argv and envp to empty
addi r1, r0, #0
addi r2, r0, #0
addi r3, r0, #0
;; Call main
ldui r10, #%hi16(main)
ori r10, r10, #%lo16(main)
or r0, r0, r0 ; nop
jal r14, r10
or r0, r0, r0 ; nop
;; DJK - Added 12Nov01. Pass main's return value to exit.
or r1, r11, r0
;; Jump to exit
ldui r10, #%hi16(exit)
ori r10, r10, #%lo16(exit)
or r0, r0, r0 ; nop
jal r14, r10
or r0, r0, r0 ; nop
;; Exit does not return, however, this code is to catch an
;; error if it does. Set the processor into sleep mode.
ori r1, r0, #$1
stw r1, r0, #HALT_REG
or r0, r0, r0
or r0, r0, r0
or r0, r0, r0
or r0, r0, r0
or r0, r0, r0
.Lend:
jmp .Lend
or r0, r0, r0
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