diff options
Diffstat (limited to 'bootasm.S')
| -rw-r--r-- | bootasm.S | 8 |
1 files changed, 5 insertions, 3 deletions
@@ -51,8 +51,10 @@ seta20.2: orl $CR0_PE, %eax movl %eax, %cr0 - # Jump to next instruction, but in 32-bit code segment. - # Switches processor into 32-bit mode. + # This ljmp is how you load the CS (Code Segment) register. + # SEG_ASM produces segment descriptors with the 32-bit mode + # flag set (the D flag), so addresses and word operands will + # default to 32 bits after this jump. ljmp $(SEG_KCODE<<3), $start32 .code32 # Assemble for 32-bit mode @@ -88,5 +90,5 @@ gdt: SEG_ASM(STA_W, 0x0, 0xffffffff) # data seg gdtdesc: - .word (gdtdesc - gdt - 1) # sizeof(gdt) - 1 + .word (gdtdesc - gdt - 1) # sizeof(gdt) - 1 .long gdt # address gdt |