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Now actually runs on real hardware.

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--HG--
branch : dtrg-videocore
This commit is contained in:
David Given 2013-05-22 22:46:10 +01:00
parent 7537c85e0a
commit 8f338f9b44
1 changed files with 24 additions and 9 deletions
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33
plat/rpi/boot.s
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@ -24,13 +24,8 @@
! the startup sequence mustn't disturb these. ! the startup sequence mustn't disturb these.
begtext: begtext:
! Set up system registers. ! Wipe the bss. This must happen absolutely first, because we need
! to store the old system registers into it.
lea gp, begtext
st sp, .returnsp
st lr, .returnlr
! Wipe the bss. (I'm a little suprised that __m_a_i_n doesn't do this.)
lea r6, begbss lea r6, begbss
lea r7, endbss lea r7, endbss
@ -39,15 +34,32 @@ _1:
stb r8, (r6) stb r8, (r6)
addcmpb.lt r6, #1, r7, _1 addcmpb.lt r6, #1, r7, _1
! Set up system registers.
lea gp, begtext
st fp, .returnfp
st sp, .returnsp
st lr, .returnlr
! Set up the new stack and save the kernel parameters to it. ! Set up the new stack and save the kernel parameters to it.
lea sp, .stack + STACKSIZE lea sp, .stack + STACKSIZE - 6*4
sub r0, gp ! pointer sub r0, gp ! pointer
st r0, 0 (sp)
sub r1, gp ! pointer sub r1, gp ! pointer
st r1, 4 (sp)
sub r2, gp ! pointer sub r2, gp ! pointer
st r2, 8 (sp)
sub r3, gp ! pointer sub r3, gp ! pointer
st r3, 12 (sp)
! r4-r5 are not pointers and don't need adjusting ! r4-r5 are not pointers and don't need adjusting
push r0-r5 st r4, 16 (sp)
st r5, 20 (sp)
sub r0, sp, gp sub r0, sp, gp
st r0, _gpu_parameters st r0, _gpu_parameters
@ -62,10 +74,12 @@ _1:
! Call the language startup code. ! Call the language startup code.
bl __m_a_i_n bl __m_a_i_n
! Fall through to __exit if this returns. ! Fall through to __exit if this returns.
.define __exit .define __exit
__exit: __exit:
ld fp, .returnfp
ld sp, .returnsp ld sp, .returnsp
ld lr, .returnlr ld lr, .returnlr
b lr b lr
@ -88,6 +102,7 @@ __exit:
! We store the stack pointer and return address on entry so that we can ! We store the stack pointer and return address on entry so that we can
! cleanly exit. ! cleanly exit.
.comm .returnfp, 4
.comm .returnsp, 4 .comm .returnsp, 4
.comm .returnlr, 4 .comm .returnlr, 4