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2014-11-26 Matthew Fortune <Matthew.Fortune@imgtec.com>

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* mips/crt0.S: Remove .set noreorder throughout.
        (zerobss): Open code the bltu macro instruction so that the
        zero-loop does not have a NOP in the branch delay slot.
This commit is contained in:
Jeff Johnston 2014-11-27 00:28:09 +00:00
parent 93d15b36ef
commit 84b2a020da
2 changed files with 24 additions and 35 deletions
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6
libgloss/ChangeLog
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@ -1,3 +1,9 @@
2014-11-26 Matthew Fortune <Matthew.Fortune@imgtec.com>
* mips/crt0.S: Remove .set noreorder throughout.
(zerobss): Open code the bltu macro instruction so that the
zero-loop does not have a NOP in the branch delay slot.
2014-11-13 Nick Clifton <nickc@redhat.com>
* msp430/Makefile.in (CRT_OBJS): Add crt_high_bss.o.

53
libgloss/mips/crt0.S
View File

@ -57,13 +57,14 @@
.globl _start
.ent _start
_start:
.set noreorder
#ifdef __mips_embedded_pic
#define PICBASE start_PICBASE
.set noreorder
PICBASE = .+8
bal PICBASE
nop
move s0,$31
.set reorder
#endif
#if __mips<3
# define STATUS_MASK (SR_CU1|SR_PE)
@ -89,9 +90,7 @@ _start:
/* Avoid hazard from FPU enable and other SR changes. */
LA (t0, hardware_hazard_hook)
beq t0,zero,1f
nop
jal t0
nop
jalr t0
1:
/* Check for FPU presence. Don't check if we know that soft_float is
@ -105,11 +104,8 @@ _start:
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. */
@ -119,9 +115,7 @@ _start:
/* Avoid hazard from FPU disable. */
LA (t0, hardware_hazard_hook)
beq t0,zero,2f
nop
jal t0
nop
jalr t0
2:
@ -129,7 +123,6 @@ _start:
doesn't get confused. */
LA (v0, 3f)
jr v0
nop
3:
LA (gp, _gp) # set the global data pointer
.end _start
@ -145,21 +138,20 @@ _start:
zerobss:
LA (v0, _fbss)
LA (v1, _end)
3:
sw zero,0(v0)
bltu v0,v1,3b
addiu v0,v0,4 # executed in delay slot
beq v0,v1,2f
1:
addiu v0,v0,4
sw zero,-4(v0)
bne v0,v1,1b
2:
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. */
@ -189,19 +181,14 @@ zerobss:
init:
LA (t9, hardware_init_hook) # init the hardware if needed
beq t9,zero,6f
nop
jal t9
nop
jalr t9
6:
LA (t9, software_init_hook) # init the hardware if needed
beq t9,zero,7f
nop
jal t9
nop
jalr t9
7:
LA (a0, _fini)
jal atexit
nop
#ifdef GCRT0
.globl _ftext
@ -209,12 +196,10 @@ init:
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
@ -225,13 +210,13 @@ init:
sw zero,(a1)
sw zero,(a2)
#endif
jal main # call the program start function
move a0,zero # set argc to 0
jal main # call the program start function
# fall through to the "exit" routine
move a0,v0 # pass through the exit code
jal exit # call libc exit to run the G++
# destructors
move a0,v0 # pass through the exit code
.end init
@ -257,27 +242,25 @@ _exit:
/* 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
.set noreorder
PICBASE = .+8
bal PICBASE
nop
move s0,$31
.set reorder
#endif
#ifdef GCRT0
LA (t0, _mcleanup)
jal t0
nop
jalr t0
#endif
LA (t0, hardware_exit_hook)
beq t0,zero,1f
nop
jal t0
nop
jalr t0
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. */