diff options
Diffstat (limited to 'src/arch/i386/prefix/romprefix.S')
| -rw-r--r-- | src/arch/i386/prefix/romprefix.S | 71 |
1 files changed, 45 insertions, 26 deletions
diff --git a/src/arch/i386/prefix/romprefix.S b/src/arch/i386/prefix/romprefix.S index e304d000..59764c6f 100644 --- a/src/arch/i386/prefix/romprefix.S +++ b/src/arch/i386/prefix/romprefix.S @@ -144,6 +144,7 @@ init: popw %ds pushw $0x40 popw %fs + /* Shuffle some registers around. We need %di available for * the print_xxx functions, and in a register that's * addressable from %es, so shuffle as follows: @@ -153,21 +154,53 @@ init: */ movw %bx, %gs movw %di, %bx + /* Print message as early as possible */ movw $init_message, %si xorw %di, %di call print_message call print_pci_busdevfn + /* Fill in product name string, if possible */ movw $prodstr_pci_id, %di call print_pci_busdevfn movb $' ', prodstr_separator + /* Print segment address */ movb $' ', %al xorw %di, %di call print_character movw %cs, %ax call print_hex_word + + /* Check for PCI BIOS version */ + pushl %ebx + pushl %edx + stc + movw $0xb101, %ax + int $0x1a + jc 1f + cmpl $PCI_SIGNATURE, %edx + jne 1f + testb %ah, %ah + jnz 1f + movw $init_message_pci, %si + xorw %di, %di + call print_message + movb %bh, %al + call print_hex_nibble + movb $'.', %al + call print_character + movb %bl, %al + call print_hex_byte + cmpb $3, %bh + jae 2f +1: /* PCI <3.0: set %gs (runtime segment) = %cs (init-time segment) */ + pushw %cs + popw %gs +2: popl %edx + popl %ebx + /* Check for PnP BIOS */ testw $0x0f, %bx /* PnP signature must be aligned - bochs */ jnz hook_int19 /* uses unalignment to indicate 'fake' PnP. */ @@ -177,6 +210,7 @@ init: movw $init_message_pnp, %si xorw %di, %di call print_message + /* Check for BBS */ pushw %es:0x1b(%bx) /* Real-mode data segment */ pushw %ds /* &(bbs_version) */ @@ -199,10 +233,11 @@ hook_int19: movw %ax, %es pushl %es:( 0x19 * 4 ) popl orig_int19 - pushw %cs + pushw %gs /* %gs contains runtime %cs */ pushw $int19_entry popl %es:( 0x19 * 4 ) hook_bbs: + /* Check for PMM */ movw $( 0xe000 - 1 ), %bx pmm_scan: @@ -259,29 +294,11 @@ gotpmm: /* PMM allocation succeeded: copy ROM to PMM block */ subb %bl, checksum popal no_pmm: - /* Check for PCI BIOS */ - pushl %edx - stc - movw $0xb101, %ax - int $0x1a - jc no_pci - cmpl $PCI_SIGNATURE, %edx - popl %edx - jne no_pci - testb %ah, %ah - jnz no_pci - movw $init_message_pci, %si - xorw %di, %di - call print_message - movb %bh, %al - call print_hex_nibble - movb $'.', %al - call print_character - movb %bl, %al - call print_hex_byte - cmpb $3, %bh - jb no_pci3 - /* Copy self to option ROM space (required for PCI3.0) */ + + /* Copy self to option ROM space. Required for PCI3.0, which + * loads us to a temporary location in low memory. Will be a + * no-op for lower PCI versions. + */ movb $' ', %al xorw %di, %di call print_character @@ -293,8 +310,7 @@ no_pmm: xorw %si, %si xorw %di, %di cs rep movsb -no_pci3: -no_pci: + /* Prompt for POST-time shell */ movw $init_message_prompt, %si xorw %di, %di @@ -338,16 +354,19 @@ wait_for_key: pushw %cs call exec no_key_pressed: + /* Print blank lines to terminate messages */ movw $init_message_end, %si xorw %di, %di call print_message + /* Restore registers */ popw %gs popw %fs popw %es popw %ds popaw + /* Indicate boot capability to PnP BIOS, if present */ movw $0x20, %ax lret |