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| author | Taru Karttunen <taruti@taruti.net> | 2011-03-30 15:46:40 +0300 |
|---|---|---|
| committer | Taru Karttunen <taruti@taruti.net> | 2011-03-30 15:46:40 +0300 |
| commit | e5888a1ffdae813d7575f5fb02275c6bb07e5199 (patch) | |
| tree | d8d51eac403f07814b9e936eed0c9a79195e2450 /sys/src/9/pc/rebootcode.s | |
Import sources from 2011-03-30 iso image
Diffstat (limited to 'sys/src/9/pc/rebootcode.s')
| -rwxr-xr-x | sys/src/9/pc/rebootcode.s | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/sys/src/9/pc/rebootcode.s b/sys/src/9/pc/rebootcode.s new file mode 100755 index 000000000..34ee4ca36 --- /dev/null +++ b/sys/src/9/pc/rebootcode.s @@ -0,0 +1,54 @@ +#include "mem.h" + +/* + * Turn off MMU, then memmory the new kernel to its correct location + * in physical memory. Then jumps the to start of the kernel. + */ + +TEXT main(SB),$0 + MOVL p1+0(FP), DI /* destination */ + MOVL DI, AX /* entry point */ + MOVL p2+4(FP), SI /* source */ + MOVL n+8(FP), CX /* byte count */ + +/* + * disable paging + */ + MOVL CR0, DX + ANDL $~0x80000000, DX /* ~(PG) */ + MOVL DX, CR0 + MOVL $0, DX + MOVL DX, CR3 + +/* + * the source and destination may overlap. + * determine whether to copy forward or backwards + */ + CMPL SI, DI + JGT _forward + MOVL SI, DX + ADDL CX, DX + CMPL DX, DI + JGT _back + +_forward: + CLD + REP; MOVSB + JMP _startkernel + +_back: + ADDL CX, DI + ADDL CX, SI + SUBL $1, DI + SUBL $1, SI + STD + REP; MOVSB + JMP _startkernel +/* + * JMP to kernel entry point. Note the true kernel entry point is + * the virtual address KZERO|AX, but this must wait until + * the MMU is enabled by the kernel in l.s + */ +_startkernel: + ORL AX, AX /* NOP: avoid link bug */ + JMP* AX |