diff options
| -rw-r--r-- | src/arch/x86/prefix/rawprefix.S | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/src/arch/x86/prefix/rawprefix.S b/src/arch/x86/prefix/rawprefix.S new file mode 100644 index 0000000..4cf5f39 --- /dev/null +++ b/src/arch/x86/prefix/rawprefix.S @@ -0,0 +1,53 @@ +/* + * Raw binary prefix + * + * Assumes that entire image is already loaded as a contiguous block + * on a paragraph boundary and entered in real mode. + * + */ + +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ) + + .text + .arch i386 + .org 0 + .code16 + +#include <librm.h> + + .section ".prefix", "ax", @progbits + .globl _raw_start +_raw_start: + + /* Adjust %cs so that %cs:0000 is the start of the image */ + movw %cs, %ax + call 1f +1: popw %bx + subw $1b, %bx + shrw $4, %bx + addw %bx, %ax + pushw %ax + pushw $2f + lret +2: + /* Install iPXE */ + call install + + /* Set up real-mode stack */ + movw %bx, %ss + movw $_estack16, %sp + + /* Jump to .text16 segment */ + pushw %ax + pushw $1f + lret + .section ".text16", "awx", @progbits +1: + /* Run iPXE */ + virtcall main + + /* Uninstall iPXE */ + call uninstall + + /* Boot next device */ + int $0x18 |