diff options
Diffstat (limited to 'sys/boot/i386/boot0/boot0.S')
| -rw-r--r-- | sys/boot/i386/boot0/boot0.S | 130 |
1 files changed, 69 insertions, 61 deletions
diff --git a/sys/boot/i386/boot0/boot0.S b/sys/boot/i386/boot0/boot0.S index 33e950b..caa89e8 100644 --- a/sys/boot/i386/boot0/boot0.S +++ b/sys/boot/i386/boot0/boot0.S @@ -30,10 +30,16 @@ #ifdef ONLY_F_KEYS /* Only F1..F6, no digits on console */ #endif -#ifdef TEST /* enable some test code */ -#ifndef ONLY_F_KEYS -#define ONLY_F_KEYS /* make room for the test code */ +#ifdef VOLUME_SERIAL /* support Volume serial number */ +#define B0_BASE 0x1ae /* move the internal data area */ +#define SAVE_MEMORY +#else +#define B0_BASE 0x1b2 #endif + +#ifdef TEST /* enable some test code */ +#define SAVE_MEMORY +#define SAVE_MORE_MEMORY #endif /* @@ -118,7 +124,7 @@ * to change the value passed to the linker in the Makefile * PRT_OFF is the location of the partition table (from the MBR standard). * B0_OFF is the location of the data area, known to boot0cfg so - * it cannot be changed. + * it cannot be changed. Computed as a negative offset from 0x200 * MAGIC is the signature of a boot block. */ @@ -127,7 +133,7 @@ .set LOAD,0x7c00 # Load address .set PRT_OFF,0x1be # Partition table - .set B0_OFF,0x1b2 # Offset of boot0 data + .set B0_OFF,(B0_BASE-0x200) # Offset of boot0 data .set MAGIC,0xaa55 # Magic: bootable @@ -144,15 +150,16 @@ * We need to define them as constant as the assembler cannot * compute them in its single pass. */ - .set _NXTDRV, -0x48 # Next drive - .set _OPT, -0x47 # Default option - .set _SETDRV, -0x46 # Drive to force - .set _FLAGS, -0x45 # Flags + .set _NXTDRV, B0_OFF+6 # Next drive + .set _OPT, B0_OFF+7 # Default option + .set _SETDRV, B0_OFF+8 # Drive to force + .set _FLAGS, B0_OFF+9 # Flags .set SETDRV, 0x20 # the 'setdrv' flag .set NOUPDATE, 0x40 # the 'noupdate' flag .set USEPACKET, 0x80 # the 'packet' flag - .set _TICKS, -0x44 # Timeout ticks - .set _FAKE,0x0 # Fake partition table + + /* ticks is at a fixed position */ + .set _TICKS, (PRT_OFF - 0x200 - 2) # Timeout ticks .set _MNUOPT, 0x10 # Saved menu entries .set TLEN, (desc_ofs - bootable_ids) # size of bootable ids @@ -260,26 +267,16 @@ save_curdrive: movb %dl, (%bp) # Save drive number read_entry: movb %ch,-0x4(%bx) # Zero active flag (ch == 0) btw %dx,_FLAGS(%bp) # Entry enabled? jnc next_entry # No - /* - * Lookup type in the 'non_bootable_ids' table, skip matching entries. - * This is implemented is by setting %di to the start of the - * exclude table, and %cl to the length of the table itself. After the - * 'repne scasb' the zero flag is set if we found a match. - * If not, %di points to the beginning of the 'valid' types, - * which is what we need for the next check. - */ movb (%bx),%al # Load type - movw $non_bootable_ids,%di # Lookup tables - movb $(bootable_ids-non_bootable_ids),%cl # length - repne # Exclude - scasb # partition? - je next_entry # Yes, ignore it + test %al, %al # skip empty partition + jz next_entry /* - * Now scan the table of bootable ids, which starts at %di and has + * Scan the table of bootable ids, which starts at %di and has * length TLEN. On a match, %di points to the element following the * match; the corresponding offset to the description is $(TLEN-1) * bytes ahead. If we don't find a match, we hit the 'unknown' entry. */ + movw $bootable_ids,%di # Lookup tables movb $(TLEN),%cl # Number of entries repne # Locate scasb # type @@ -500,19 +497,10 @@ check_selection: * the string at %si * putx: print the option in %dl followed by the string at %di * also record the drive as valid. - * puts: print the string at %si followed by a crlf * putn: print a crlf * putstr: print the string at %si * putchr: print the char in al */ -putkey: -#ifndef SIO - movb $'F',%al # Display - callw putchr # 'F' -#endif - movb $'1',%al # Prepare - addb %dl,%al # digit - jmp putstr.1 # Display the rest /* * Display the option and record the drive as valid in the options. @@ -523,17 +511,24 @@ putx: btsw %dx,_MNUOPT(%bp) # Enable menu option movw $item,%si # Display callw putkey # key movw %di,%si # Display the rest - -puts: callw putstr # Display string + callw putstr # Display string putn: movw $crlf,%si # To next line + jmp putstr +putkey: +#ifndef SIO + movb $'F',%al # Display + callw putchr # 'F' +#endif + movb $'1',%al # Prepare + addb %dl,%al # digit + +putstr.1: callw putchr # Display char putstr: lodsb # Get byte testb $0x80,%al # End of string? - jnz putstr.2 # Yes -putstr.1: callw putchr # Display char - jmp putstr # Continue -putstr.2: andb $~0x80,%al # Clear MSB + jz putstr.1 # No + andb $~0x80,%al # Clear MSB then print last putchr: #ifndef SIO @@ -601,38 +596,45 @@ crlf: .ascii "\r"; .byte '\n'|0x80 /* Partition type tables */ -non_bootable_ids: - /* - * These entries identify invalid or NON BOOT types and partitions. - * 0: empty, 5: DOS3 ext. partition, 0xf: WIN95 ext partition - */ - .byte 0x0, 0x5, 0xf bootable_ids: /* - * These values indicate bootable types we know the names of. - * 1: FAT12, 4: FAT16 <32M, 6: FAT16 > 32M, 7: NTFS - * 0xb: FAT32, 0xc: FAT32-LBA, 0xe: FAT16-LBA, - * 0x83: linux, 0xa5: FreeBSD, 0xa6: netbsd, 0xa9:openbsd + * These values indicate bootable types we know about. + * Corresponding descriptions are at desc_ofs: + * Entries don't need to be sorted. */ - .byte 0x1, 0x6, 0x7, 0xb, 0xc, 0xe, 0x83 - .byte 0xa5, 0xa6, 0xa9, 0x4 + .byte 0x1, 0x6, 0x7, 0xb, 0xc +#ifndef SAVE_MEMORY + .byte 0xe +#endif + .byte 0x83, 0xa5, 0xa6, 0xa9, 0x4 +#ifndef SAVE_MORE_MEMORY + .byte 0x5, 0xf +#endif + desc_ofs: /* * Offsets that match the known types above, used to point to the * actual partition name. The last entry must point to os_misc, * which is used for non-matching names. */ - .byte os_dos-. # 1, DOS - .byte os_dos-. # 6, DOS/WIN - .byte os_win-. # 7, Windows - .byte os_win-. # 11, Windows - .byte os_win-. # 12, Windows - .byte os_win-. # 14, Windows + .byte os_dos-. # 1, FAT12 DOS + .byte os_dos-. # 6, FAT16 <32M, DOS/WIN + .byte os_win-. # 7, FAT16 >=32M Windows + .byte os_win-. # 11, FAT32 + .byte os_win-. # 12, FAT32-LBA +#ifndef SAVE_MEMORY + .byte os_win-. # 14, FAT16-LBA +#endif .byte os_linux-. # 131, Linux .byte os_freebsd-. # 165, FreeBSD .byte os_bsd-. # 166, OpenBSD .byte os_bsd-. # 169, NetBSD - .byte os_dos-. # 4, DOS + .byte os_dos-. # 4, FAT16 < 32M +#ifndef SAVE_MORE_MEMORY + .byte os_ext-. # 5, DOS Ext + .byte os_ext-. # 15, DOS Ext-LBA +#endif + .byte os_misc-. # Unknown /* @@ -641,15 +643,18 @@ desc_ofs: */ os_misc: .byte '?'|0x80 os_dos: -#if !defined(TEST) /* DOS string only if room */ +#ifndef SAVE_MEMORY /* DOS string only if room */ .ascii "DO"; .byte 'S'|0x80 #endif os_win: .ascii "WI"; .byte 'N'|0x80 os_linux: .ascii "Linu"; .byte 'x'|0x80 os_freebsd: .ascii "Free" os_bsd: .ascii "BS"; .byte 'D'|0x80 +#ifndef SAVE_MORE_MEMORY +os_ext: .ascii "EX"; .byte 'T'|0x80 +#endif - .org B0_OFF,0x90 + .org (0x200 + B0_OFF),0x90 /* * The boot0 version 1.0 parameter table. * Do not move it nor change the "Drive " string, boot0cfg @@ -663,6 +668,9 @@ nxtdrv: .byte 0x0 # Next drive number opt: .byte 0x0 # Option setdrv_num: .byte 0x80 # Drive to force flags: .byte FLAGS # Flags +#ifdef VOLUME_SERIAL + .byte 0xa8,0xa8,0xa8,0xa8 # Volume Serial Number +#endif ticks: .word TICKS # Delay .org PRT_OFF |
