绋嬪簭6 ‑1 linux/boot/bootsect.S

  1 !

  2 ! SYS_SIZE is the number of clicks (16 bytes) to be loaded.

  3 ! 0x3000 is 0x30000 bytes = 196kB, more than enough for current

  4 ! versions of linux

    ! SYS_SIZE鏄�瑕佸姞杞界殑绯荤粺妯″潡闀垮害锛屽崟浣嶆槸鑺傦紝姣忚��16瀛楄妭銆�0x3000鍏变负0x30000瀛楄妭=196KB銆�

    ! 鑻ヤ互1024瀛楄妭涓�1KB璁★紝鍒欏簲璇ユ槸192KB銆傚�逛簬褰撳墠鍐呮牳鐗堟湰杩欎釜绌洪棿闀垮害宸茶冻澶熶簡銆傚綋璇ュ�间负

    ! 0x8000鏃讹紝琛ㄧず鍐呮牳鏈�澶т负512KB銆傚洜涓哄唴瀛�0x90000澶勫紑濮嬪瓨鏀剧Щ鍔ㄥ悗鐨�bootsect鍜�setup

    ! 鐨勪唬鐮侊紝鍥犳�よ�ュ�兼渶澶т笉寰楄秴杩�0x9000锛堣〃绀�584KB锛夈��

    ! 杩欓噷鎰熷徆鍙�'!'鎴栧垎鍙�';'琛ㄧず绋嬪簭娉ㄩ噴璇�鍙ュ紑濮嬨��

  5 !

    ! 澶存枃浠�linux/config.h涓�瀹氫箟浜嗗唴鏍哥敤鍒扮殑涓�浜涘父鏁扮�﹀彿鍜�Linus鑷�宸变娇鐢ㄧ殑榛樿�ょ‖鐩樺弬鏁板潡銆�

    ! 渚嬪�傚叾涓�瀹氫箟浜嗕互涓嬩竴浜涘父鏁帮細

    ! DEF_SYSSIZE  = 0x3000 - 榛樿�ょ郴缁熸ā鍧楅暱搴︺�傚崟浣嶆槸鑺傦紝姣忚妭涓�16瀛楄妭锛�

    ! DEF_INITSEG  = 0x9000 - 榛樿�ゆ湰绋嬪簭浠ｇ爜绉诲姩鐩�鐨勬�典綅缃�锛�

    ! DEF_SETUPSEG = 0x9020 - 榛樿��setup绋嬪簭浠ｇ爜娈典綅缃�锛�

    ! DEF_SYSSEG   = 0x1000 - 榛樿�や粠纾佺洏鍔犺浇绯荤粺妯″潡鍒板唴瀛樼殑娈典綅缃�銆�

  6 #include <linux/config.h>

  7 SYSSIZE = DEF_SYSSIZE           ! 瀹氫箟涓�涓�鏍囧彿鎴栫�﹀彿銆傛寚鏄庣紪璇戣繛鎺ュ悗system妯″潡鐨勫ぇ灏忋��

  8 !

  9 !       bootsect.s              (C) 1991 Linus Torvalds

 10 !       modified by Drew Eckhardt

 11 !

 12 ! bootsect.s is loaded at 0x7c00 by the bios-startup routines, and moves

 13 ! iself out of the way to address 0x90000, and jumps there.

 14 !

 15 ! It then loads 'setup' directly after itself (0x90200), and the system

 16 ! at 0x10000, using BIOS interrupts.

 17 !

 18 ! NOTE! currently system is at most 8*65536 bytes long. This should be no

 19 ! problem, even in the future. I want to keep it simple. This 512 kB

 20 ! kernel size should be enough, especially as this doesn't contain the

 21 ! buffer cache as in minix

 22 !

 23 ! The loader has been made as simple as possible, and continuos

 24 ! read errors will result in a unbreakable loop. Reboot by hand. It

 25 ! loads pretty fast by getting whole sectors at a time whenever possible.

    !

    ! 浠ヤ笅鏄�鍓嶉潰鏂囧瓧鐨勮瘧鏂囷��

    !     bootsect.s              (C) 1991 Linus Torvalds

    !     Drew Eckhardt淇�鏀�

    !

    ! bootsect.s 琚�ROM BIOS鍚�鍔ㄥ瓙绋嬪簭鍔犺浇鑷�0x7c00 (31KB)澶勶紝骞跺皢鑷�宸辩Щ鍒颁簡鍦板潃0x90000

    ! (576KB)澶勶紝骞惰烦杞�鑷抽偅閲屻��

    !

    ! 瀹冪劧鍚庝娇鐢�BIOS涓�鏂�灏�'setup'鐩存帴鍔犺浇鍒拌嚜宸辩殑鍚庨潰(0x90200)(576.5KB)锛屽苟灏�system鍔�

    ! 杞藉埌鍦板潃0x10000澶勩��

    !

    ! 娉ㄦ剰! 鐩�鍓嶇殑鍐呮牳绯荤粺鏈�澶ч暱搴﹂檺鍒朵负(8*65536)(512KB)瀛楄妭锛屽嵆浣挎槸鍦ㄥ皢鏉ヨ繖涔熷簲璇ユ病鏈夐棶

    ! 棰樼殑銆傛垜鎯宠�╁畠淇濇寔绠�鍗曟槑浜嗐�傝繖鏍�512KB鐨勬渶澶у唴鏍搁暱搴﹀簲璇ヨ冻澶熶簡锛屽挨鍏舵槸杩欓噷娌℃湁璞�

    ! MINIX涓�涓�鏍峰寘鍚�缂撳啿鍖洪珮閫熺紦鍐层��

    !

    ! 鍔犺浇绋嬪簭宸茬粡鍋氬緱澶熺畝鍗曚簡锛屾墍浠ユ寔缁�鍦拌�绘搷浣滃嚭閿欏皢瀵艰嚧姝诲惊鐜�銆傚彧鑳芥墜宸ラ噸鍚�銆傚彧瑕佸彲鑳斤紝

    ! 閫氳繃涓�娆¤�诲彇鎵�鏈夌殑鎵囧尯锛屽姞杞借繃绋嬪彲浠ュ仛寰楀緢蹇�銆�

 26

    ! 浼�鎸囦护锛堜吉鎿嶄綔绗︼��.globl鎴�.global鐢ㄤ簬瀹氫箟闅忓悗鐨勬爣璇嗙�︽槸澶栭儴鐨勬垨鍏ㄥ眬鐨勶紝骞朵笖鍗充娇涓�

    ! 浣跨敤涔熷己鍒跺紩鍏ャ�� .text銆�.data鍜�.bss鐢ㄤ簬鍒嗗埆瀹氫箟褰撳墠浠ｇ爜娈点�佹暟鎹�娈靛拰鏈�鍒濆�嬪寲鏁版嵁娈点��

    ! 鍦ㄩ摼鎺ュ�氫釜鐩�鏍囨ā鍧楁椂锛岄摼鎺ョ▼搴忥紙ld86锛変細鏍规嵁瀹冧滑鐨勭被鍒�鎶婂悇涓�鐩�鏍囨ā鍧椾腑鐨勭浉搴旀�靛垎鍒�

    ! 缁勫悎锛堝悎骞讹級鍦ㄤ竴璧枫�傝繖閲屾妸涓変釜娈甸兘瀹氫箟鍦ㄥ悓涓�閲嶅彔鍦板潃鑼冨洿涓�锛屽洜姝ゆ湰绋嬪簭瀹為檯涓婁笉鍒嗘�点��

    ! 鍙﹀�栵紝鍚庨潰甯﹀啋鍙风殑瀛楃�︿覆鏄�鏍囧彿锛屼緥濡備笅闈㈢��'begtext:'銆�

    ! 涓�鏉℃眹缂栬��鍙ラ�氬父鐢辨爣鍙凤紙鍙�閫夛級銆佹寚浠ゅ姪璁扮�︼紙鎸囦护鍚嶏級鍜屾搷浣滄暟涓変釜瀛楁�电粍鎴愩�傛爣鍙蜂綅浜�

    ! 涓�鏉℃寚浠ょ殑绗�涓�涓�瀛楁�点�傚畠浠ｈ〃鍏舵墍鍦ㄤ綅缃�鐨勫湴鍧�锛岄�氬父鎸囨槑涓�涓�璺宠浆鎸囦护鐨勭洰鏍囦綅缃�銆�

 27 .globl begtext, begdata, begbss, endtext, enddata, endbss

 28 .text                              ! 鏂囨湰娈碉紙浠ｇ爜娈碉級銆�

 29 begtext:

 30 .data                              ! 鏁版嵁娈点��

 31 begdata:

 32 .bss                               ! 鏈�鍒濆�嬪寲鏁版嵁娈点��

 33 begbss:

 34 .text                              ! 鏂囨湰娈碉紙浠ｇ爜娈碉級銆�

 35

    ! 涓嬮潰绛夊彿'='鎴栫�﹀��'EQU'鐢ㄤ簬瀹氫箟鏍囪瘑绗︽垨鏍囧彿鎵�浠ｈ〃鐨勫�笺��

 36 SETUPLEN = 4                       ! nr of setup-sectors

                                       ! setup绋嬪簭浠ｇ爜鍗犵敤纾佺洏鎵囧尯鏁�(setup-sectors)鍊硷紱

 37 BOOTSEG  = 0x07c0                  ! original address of boot-sector

                                       ! bootsect浠ｇ爜鎵�鍦ㄥ唴瀛樺師濮嬫�靛湴鍧�锛�

 38 INITSEG  = DEF_INITSEG             ! we move boot here - out of the way

                                       ! 灏�bootsect绉诲埌浣嶇疆0x90000 - 閬垮紑绯荤粺妯″潡鍗犵敤澶勶紱

 39 SETUPSEG = DEF_SETUPSEG            ! setup starts here

                                       ! setup绋嬪簭浠庡唴瀛�0x90200澶勫紑濮嬶紱

 40 SYSSEG   = DEF_SYSSEG              ! system loaded at 0x10000 (65536).

                                       ! system妯″潡鍔犺浇鍒�0x10000锛�64 KB锛夊�勶��

 41 ENDSEG   = SYSSEG + SYSSIZE        ! where to stop loading

                                       ! 鍋滄�㈠姞杞界殑娈靛湴鍧�锛�

 42

 43 ! ROOT_DEV & SWAP_DEV are now written by "build".

    ! 鏍规枃浠剁郴缁熻�惧�囧彿ROOT_DEV鍜屼氦鎹㈣�惧�囧彿SWAP_DEV 鐜板湪鐢�tools鐩�褰曚笅鐨�build绋嬪簭鍐欏叆銆�

    ! 璁惧�囧��0x306鎸囧畾鏍规枃浠剁郴缁熻�惧�囨槸绗�2涓�纭�鐩樼殑绗�1涓�鍒嗗尯銆傚綋骞�Linus鏄�鍦ㄧ��2涓�纭�鐩樹笂

    ! 瀹夎�呬��Linux 0.11绯荤粺锛屾墍浠ヨ繖閲�ROOT_DEV琚�璁剧疆涓�0x306銆傚湪缂栬瘧杩欎釜鍐呮牳鏃朵綘鍙�浠ユ牴鎹�

    ! 鑷�宸辨牴鏂囦欢绯荤粺鎵�鍦ㄨ�惧�囦綅缃�淇�鏀硅繖涓�璁惧�囧彿銆傝繖涓�璁惧�囧彿鏄�Linux绯荤粺鑰佸紡鐨勭‖鐩樿�惧�囧彿鍛�

    ! 鍚嶆柟寮忥紝纭�鐩樿�惧�囧彿鍏蜂綋鍊肩殑鍚�涔夊�備笅锛�

    ! 璁惧�囧��=涓昏�惧�囧彿*256 + 娆¤�惧�囧彿锛堜篃鍗�dev_no = (major<<8) + minor 锛�

    ! 锛堜富璁惧�囧彿锛�1-鍐呭瓨,2-纾佺洏,3-纭�鐩�,4-ttyx,5-tty,6-骞惰�屽��,7-闈炲懡鍚嶇�￠亾锛�

    ! 0x300 - /dev/hd0 - 浠ｈ〃鏁翠釜绗�1涓�纭�鐩橈紱

    ! 0x301 - /dev/hd1 - 绗�1涓�鐩樼殑绗�1涓�鍒嗗尯锛�

    !  鈥�

    ! 0x304 - /dev/hd4 - 绗�1涓�鐩樼殑绗�4涓�鍒嗗尯锛�

    ! 0x305 - /dev/hd5 - 浠ｈ〃鏁翠釜绗�2涓�纭�鐩橈紱

    ! 0x306 - /dev/hd6 - 绗�2涓�鐩樼殑绗�1涓�鍒嗗尯锛�

    !  鈥�

    ! 0x309 - /dev/hd9 - 绗�2涓�鐩樼殑绗�4涓�鍒嗗尯锛�

    ! 浠�Linux鍐呮牳0.95鐗堝悗灏卞凡缁忎娇鐢ㄤ笌鐜板湪鍐呮牳鐩稿悓鐨勫懡鍚嶆柟娉曚簡銆�

 44 ROOT_DEV = 0                       ! 鏍规枃浠剁郴缁熻�惧�囦娇鐢ㄤ笌绯荤粺寮曞�兼椂鍚屾牱鐨勮�惧�囷��

 45 SWAP_DEV = 0                       ! 浜ゆ崲璁惧�囦娇鐢ㄤ笌绯荤粺寮曞�兼椂鍚屾牱鐨勮�惧�囷紱

 46

    ! 浼�鎸囦��entry杩�浣块摼鎺ョ▼搴忓湪鐢熸垚鐨勬墽琛岀▼搴忥��a.out锛変腑鍖呭惈鎸囧畾鐨勬爣璇嗙�︽垨鏍囧彿銆傝繖閲屾槸

    ! 绋嬪簭鎵ц�屽紑濮嬬偣銆�49 -- 58琛屼綔鐢ㄦ槸灏嗚嚜韬�(bootsect)浠庣洰鍓嶆�典綅缃� 0x07c0(31KB) 绉诲姩鍒�

    ! 0x9000(576KB) 澶勶紝鍏�256瀛楋紙512瀛楄妭锛夛紝鐒跺悗璺宠浆鍒扮Щ鍔ㄥ悗浠ｇ爜鐨�go鏍囧彿澶勶紝涔熷嵆鏈�绋�

    ! 搴忕殑涓嬩竴璇�鍙ュ�勩��

 47 entry start                        ! 鍛婄煡閾炬帴绋嬪簭锛岀▼搴忎粠start鏍囧彿寮�濮嬫墽琛屻��

 48 start:

 49         mov     ax,#BOOTSEG        ! 灏�ds娈靛瘎瀛樺櫒缃�涓�0x7C0锛�

 50         mov     ds,ax

 51         mov     ax,#INITSEG        ! 灏�es娈靛瘎瀛樺櫒缃�涓�0x9000锛�

 52         mov     es,ax

 53         mov     cx,#256            ! 璁剧疆绉诲姩璁℃暟鍊�=256瀛楋紙512瀛楄妭锛夛紱

 54         sub     si,si              ! 婧愬湴鍧�   ds:si = 0x07C0:0x0000

 55         sub     di,di              ! 鐩�鐨勫湴鍧� es:di = 0x9000:0x0000

 56         rep                        ! 閲嶅�嶆墽琛屽苟閫掑噺cx鐨勫�硷紝鐩村埌cx = 0涓烘��銆�

 57         movw                       ! 鍗�movs鎸囦护銆備粠鍐呭瓨[si]澶勭Щ鍔�cx涓�瀛楀��[di]澶勩��

 58         jmpi    go,INITSEG         ! 娈甸棿璺宠浆锛�Jump Intersegment锛夈�傝繖閲�INITSEG

                                       ! 鎸囧嚭璺宠浆鍒扮殑娈靛湴鍧�锛屾爣鍙�go鏄�娈靛唴鍋忕Щ鍦板潃銆�

 59

    ! 浠庝笅闈㈠紑濮嬶紝CPU鍦ㄥ凡绉诲姩鍒�0x90000浣嶇疆澶勭殑浠ｇ爜涓�鎵ц�屻��

    ! 杩欐�典唬鐮佽�剧疆鍑犱釜娈靛瘎瀛樺櫒锛屽寘鎷�鏍堝瘎瀛樺��ss鍜�sp銆傛爤鎸囬拡sp鍙�瑕佹寚鍚戣繙澶т��512瀛楄妭鍋忕Щ

    ! 锛堝嵆鍦板潃0x90200锛夊�勯兘鍙�浠ャ�傚洜涓轰粠0x90200鍦板潃寮�濮嬪�勮繕瑕佹斁缃�setup绋嬪簭锛岃�屾�ゆ��setup

    ! 绋嬪簭澶х害涓�4涓�鎵囧尯锛屽洜姝�sp瑕佹寚鍚戝ぇ浜庯紙0x200 + 0x200 * 4 +鍫嗘爤澶у皬锛変綅缃�澶勩�傝繖閲�sp

    ! 璁剧疆涓� 0x9ff00 - 12锛堝弬鏁拌〃闀垮害锛夛紝鍗�sp = 0xfef4銆傚湪姝や箣涓婁綅缃�浼氬瓨鏀句竴涓�鑷�寤虹殑椹卞姩

    ! 鍣ㄥ弬鏁拌〃锛岃�佷笅闈㈣�存槑銆傚疄闄呬笂BIOS鎶婂紩瀵兼墖鍖哄姞杞藉埌0x7c00 澶勫苟鎶婃墽琛屾潈浜ょ粰寮曞�肩▼搴忔椂锛�

    ! ss = 0x00锛�sp = 0xfffe銆�

    ! 鍙﹀�栵紝绗�65琛屼笂push鎸囦护鐨勬湡鏈涗綔鐢ㄦ槸鎯虫殏鏃舵妸娈靛�间繚鐣欏湪鏍堜腑锛岀劧鍚庣瓑涓嬮潰鎵ц�屽畬鍒ゆ柇纾侀��

    ! 鎵囧尯鏁板悗鍐嶅脊鍑烘爤锛屽苟缁欐�靛瘎瀛樺�� fs鍜�gs璧嬪�硷紙绗�109琛岋級銆備絾鏄�鐢变簬绗�67銆�68涓よ��鍙ヤ慨鏀�

    ! 浜嗘爤娈电殑浣嶇疆锛屽洜姝ら櫎闈炲湪鎵ц�屾爤寮瑰嚭鎿嶄綔涔嬪墠鎶婃爤娈垫仮澶嶅埌鍘熶綅缃�锛屽惁鍒欒繖鏍疯�捐�″氨鏄�閿欒��鐨勩��

    ! 鍥犳�よ繖閲屽瓨鍦ㄤ竴涓�bug銆傛敼姝ｇ殑鏂规硶涔嬩竴鏄�鍘绘帀绗�65琛岋紝骞舵妸绗�109琛屼慨鏀规垚鈥�mov ax,cs鈥濄��

 60 go:     mov     ax,cs              ! 灏�ds銆�es鍜�ss閮界疆鎴愮Щ鍔ㄥ悗浠ｇ爜鎵�鍦ㄧ殑娈靛��(0x9000)銆�

 61         mov     dx,#0xfef4         ! arbitrary value >>512 - disk parm size

 62

 63         mov     ds,ax

 64         mov     es,ax

 65         push    ax                 ! 涓存椂淇濆瓨娈靛�硷紙0x9000锛夛紝渚�109琛屼娇鐢ㄣ�傦紙婊戝ご!锛�

 66

 67         mov     ss,ax              ! put stack at 0x9ff00 - 12.

 68         mov     sp,dx

 69 /*

 70  *      Many BIOS's default disk parameter tables will not

 71  *      recognize multi-sector reads beyond the maximum sector number

 72  *      specified in the default diskette parameter tables - this may

 73  *      mean 7 sectors in some cases.

 74  *

 75  *      Since single sector reads are slow and out of the question,

 76  *      we must take care of this by creating new parameter tables

 77  *      (for the first disk) in RAM.  We will set the maximum sector

 78  *      count to 18 - the most we will encounter on an HD 1.44. 

 79  *

 80  *      High doesn't hurt.  Low does.

 81  *

 82  *      Segments are as follows: ds=es=ss=cs - INITSEG,

 83  *              fs = 0, gs = parameter table segment

 84  */

    /*

     *      瀵逛簬澶氭墖鍖鸿�绘搷浣滄墍璇荤殑鎵囧尯鏁拌秴杩囬粯璁ょ�佺洏鍙傛暟琛ㄤ腑鎸囧畾鐨勬渶澶ф墖鍖烘暟鏃讹紝

     *      寰堝��BIOS灏嗕笉鑳借繘琛屾�ｇ‘璇嗗埆銆傚湪鏌愪簺鎯呭喌涓嬫槸7涓�鎵囧尯銆�

     *

     *      鐢变簬鍗曟墖鍖鸿�绘搷浣滃お鎱�锛屼笉浜堜互鑰冭檻锛屽洜姝ゆ垜浠�蹇呴』閫氳繃鍦ㄥ唴瀛樹腑閲嶅垱寤烘柊鐨�

     *      鍙傛暟琛�锛堜负绗�1涓�椹卞姩鍣�锛夋潵瑙ｅ喅杩欎釜闂�棰樸�傛垜浠�灏嗘妸鍏朵腑鏈�澶ф墖鍖烘暟璁剧疆涓�

     *      18 -- 鍗冲湪1.44MB纾佺洏涓婁細纰板埌鐨勬渶澶ф暟鍊笺��

     *     

     *      杩欎釜鏁板�煎ぇ浜嗕笉浼氬嚭闂�棰橈紝浣嗘槸澶�灏忓氨涓嶈�屼簡銆�

     *

     *      娈靛瘎瀛樺櫒灏嗚��璁剧疆鎴愶細ds=es=ss=cs - 閮戒负INITSEG锛�0x9000锛夛紝

     *      fs = 0锛�gs = 鍙傛暟琛ㄦ墍鍦ㄦ�靛�笺��

     */

 85 ! BIOS璁剧疆鐨勪腑鏂�0x1E鐨勪腑鏂�鍚戦噺鍊兼槸杞�椹卞弬鏁拌〃鍦板潃銆傝�ュ悜閲忓�间綅浜庡唴瀛�0x1E * 4 = 0x78

    ! 澶勩�傝繖娈典唬鐮侀�栧厛浠庡唴瀛�0x0000:0x0078澶勫�嶅埗鍘熻蒋椹卞弬鏁拌〃鍒�0x9000:0xfef4澶勶紝鐒跺悗淇�鏀�

    ! 琛ㄤ腑鐨勬瘡纾侀亾鏈�澶ф墖鍖烘暟涓�18銆�

 86

 87         push    #0                 ! 缃�娈靛瘎瀛樺��fs = 0銆�

 88         pop     fs                 ! fs:bx鎸囧悜瀛樻湁杞�椹卞弬鏁拌〃鍦板潃澶勶紙鎸囬拡鐨勬寚閽堬級銆�

 89         mov     bx,#0x78           ! fs:bx is parameter table address

    ! 涓嬮潰鎸囦护琛ㄧず涓嬩竴鏉¤��鍙ョ殑鎿嶄綔鏁板湪fs娈靛瘎瀛樺櫒鎵�鎸囩殑娈典腑銆傚畠鍙�褰卞搷鍏朵笅涓�鏉¤��鍙ャ�傝繖閲�

    ! 鎶� fs:bx 鎵�鎸囧唴瀛樹綅缃�澶勭殑琛ㄥ湴鍧�鏀惧埌瀵勫瓨鍣ㄥ�� gs:si 涓�浣滀负鍘熷湴鍧�銆傚瘎瀛樺櫒瀵� es:di =

    ! 0x9000:0xfef4 涓虹洰鐨勫湴鍧�銆�

 90         seg fs

 91         lgs     si,(bx)            ! gs:si is source

 92

 93         mov     di,dx              ! es:di is destination ! dx=0xfef4锛屽湪61琛岃��璁剧疆銆�

 94         mov     cx,#6              ! copy 12 bytes

 95         cld                        ! 娓呮柟鍚戞爣蹇椼�傚�嶅埗鏃舵寚閽堥�掑�炪��

 96

 97         rep                        ! 澶嶅埗12瀛楄妭鐨勮蒋椹卞弬鏁拌〃鍒�0x9000:0xfef4澶勩��

 98         seg gs

 99         movw

100

101         mov     di,dx              ! es:di鎸囧悜鏂拌〃锛屼慨鏀硅〃涓�鍋忕��4澶勭殑鏈�澶ф墖鍖烘暟涓�18銆�

102         movb    4(di),*18          ! patch sector count

103

104         seg fs                     ! 璁╀腑鏂�鍚戦��0x1E鐨勫�兼寚鍚戞柊琛ㄣ��

105         mov     (bx),di

106         seg fs

107         mov     2(bx),es

108

109         pop     ax                 ! 姝ゆ椂ax涓�鏄�涓婇潰绗�65琛屼繚鐣欎笅鏉ョ殑娈靛�硷紙0x9000锛夈��

110         mov     fs,ax              ! 璁剧疆fs = gs = 0x9000銆�

111         mov     gs,ax

112        

113         xor     ah,ah              ! reset FDC ! 澶嶄綅杞�鐩樻帶鍒跺櫒锛岃�╁叾閲囩敤鏂板弬鏁般��

114         xor     dl,dl              ! dl = 0锛岀��1涓�杞�椹便��

115         int     0x13   

116

117 ! load the setup-sectors directly after the bootblock.

118 ! Note that 'es' is already set up.

    ! 鍦�bootsect绋嬪簭鍧楀悗绱ф牴鐫�鍔犺浇setup妯″潡鐨勪唬鐮佹暟鎹�銆�

    ! 娉ㄦ剰es宸茬粡璁剧疆濂戒簡銆傦紙鍦ㄧЩ鍔ㄤ唬鐮佹椂es宸茬粡鎸囧悜鐩�鐨勬�靛湴鍧�澶�0x9000锛夈��

119

    ! 121--137琛岀殑鐢ㄩ�旀槸鍒╃敤ROM BIOS涓�鏂�INT 0x13 灏�setup 妯″潡浠庣�佺洏绗�2涓�鎵囧尯寮�濮嬭�诲��

    ! 0x90200 寮�濮嬪�勶紝鍏辫�� 4涓�鎵囧尯銆傚湪璇绘搷浣滆繃绋嬩腑濡傛灉璇诲嚭閿欙紝鍒欐樉绀虹�佺洏涓婂嚭閿欐墖鍖轰綅缃�锛�

    ! 鐒跺悗澶嶄綅椹卞姩鍣ㄥ苟閲嶈瘯锛屾病鏈夐��璺�銆�

    ! INT 0x13璇绘墖鍖轰娇鐢ㄨ皟鐢ㄥ弬鏁拌�剧疆濡備笅锛�

    ! ah = 0x02 - 璇荤�佺洏鎵囧尯鍒板唴瀛橈��al = 闇�瑕佽�诲嚭鐨勬墖鍖烘暟閲忥��

    ! ch = 纾侀亾(鏌遍潰)鍙风殑浣�8浣嶏紱   cl = 寮�濮嬫墖鍖�(浣�0-5)锛岀�侀亾鍙烽��2浣�(浣�6-7)锛�

    ! dh = 纾佸ご鍙凤紱                 dl = 椹卞姩鍣ㄥ彿锛堝�傛灉鏄�纭�鐩樺垯浣�7瑕佺疆浣嶏級锛�

    ! es:bx 脿鎸囧悜鏁版嵁缂撳啿鍖猴紱  濡傛灉鍑洪敊鍒�CF鏍囧織缃�浣嶏��ah涓�鏄�鍑洪敊鐮併��

120 load_setup:

121         xor     dx, dx                  ! drive 0, head 0

122         mov     cx,#0x0002              ! sector 2, track 0

123         mov     bx,#0x0200              ! address = 512, in INITSEG

124         mov     ax,#0x0200+SETUPLEN     ! service 2, nr of sectors

125         int     0x13                    ! read it

126         jnc     ok_load_setup           ! ok - continue

127

128         push    ax                      ! dump error code ! 鏄剧ず鍑洪敊淇℃伅銆傚嚭閿欑爜鍏ユ爤銆�

129         call    print_nl                ! 灞忓箷鍏夋爣鍥炶溅銆�

130         mov     bp, sp                  ! ss:bp鎸囧悜娆叉樉绀虹殑瀛楋紙word锛夈��

131         call    print_hex               ! 鏄剧ず鍗佸叚杩涘埗鍊笺��

132         pop     ax     

133        

134         xor     dl, dl                  ! reset FDC ! 澶嶄綅纾佺洏鎺у埗鍣�锛岄噸璇曘��

135         xor     ah, ah

136         int     0x13

137         j       load_setup              ! j 鍗�jmp鎸囦护銆�

138

139 ok_load_setup:

140

141 ! Get disk drive parameters, specifically nr of sectors/track

    ! 杩欐�典唬鐮佸彇纾佺洏椹卞姩鍣ㄧ殑鍙傛暟锛屽疄闄呬笂鏄�鍙栨瘡纾侀亾鎵囧尯鏁帮紝骞朵繚瀛樺湪浣嶇疆sectors澶勩��

    ! 鍙栫�佺洏椹卞姩鍣ㄥ弬鏁�INT 0x13璋冪敤鏍煎紡鍜岃繑鍥炰俊鎭�濡備笅锛�

    ! ah = 0x08     dl = 椹卞姩鍣ㄥ彿锛堝�傛灉鏄�纭�鐩樺垯瑕佺疆浣�7涓�1锛夈��

    ! 杩斿洖淇℃伅锛�

    ! 濡傛灉鍑洪敊鍒�CF缃�浣嶏紝骞朵��ah = 鐘舵�佺爜銆�

    ! ah = 0锛� al = 0锛�          bl = 椹卞姩鍣ㄧ被鍨嬶紙AT/PS2锛�

    ! ch = 鏈�澶х�侀亾鍙风殑浣�8浣嶏紝  cl = 姣忕�侀亾鏈�澶ф墖鍖烘暟(浣�0-5)锛屾渶澶х�侀亾鍙烽��2浣�(浣�6-7)

    ! dh = 鏈�澶х�佸ご鏁帮��          dl = 椹卞姩鍣ㄦ暟閲忥紝

    ! es:di -脿 杞�椹辩�佺洏鍙傛暟琛ㄣ��

142

143         xor     dl,dl

144         mov     ah,#0x08           ! AH=8 is get drive parameters

145         int     0x13

146         xor     ch,ch

    ! 涓嬮潰鎸囦护琛ㄧず涓嬩竴鏉¤��鍙ョ殑鎿嶄綔鏁板湪 cs娈靛瘎瀛樺櫒鎵�鎸囩殑娈典腑銆傚畠鍙�褰卞搷鍏朵笅涓�鏉¤��鍙ャ�傚疄闄�

    ! 涓婏紝鐢变簬鏈�绋嬪簭浠ｇ爜鍜屾暟鎹�閮借��璁剧疆澶勪簬鍚屼竴涓�娈典腑锛屽嵆娈靛瘎瀛樺��cs鍜�ds銆�es鐨勫�肩浉鍚岋紝鍥�

    ! 姝ゆ湰绋嬪簭涓�姝ゅ�勫彲浠ヤ笉浣跨敤璇ユ寚浠ゃ��

147         seg cs

    ! 涓嬪彞淇濆瓨姣忕�侀亾鎵囧尯鏁般�傚�逛簬杞�鐩樻潵璇达紙dl=0锛夛紝鍏舵渶澶х�侀亾鍙蜂笉浼氳秴杩�256锛�ch宸茬粡瓒冲�熻��

    ! 绀哄畠锛屽洜姝�cl鐨勪綅6-7鑲�瀹氫��0銆傚張146琛屽凡缃�ch=0锛屽洜姝ゆ�ゆ��cx涓�鏄�姣忕�侀亾鎵囧尯鏁般��

148         mov     sectors,cx

149         mov     ax,#INITSEG

150         mov     es,ax              ! 鍥犱负涓婇潰鍙栫�佺洏鍙傛暟涓�鏂�鏀逛��es鍊硷紝杩欓噷閲嶆柊鏀瑰洖銆�

151

152 ! Print some inane message

    ! 鏄剧ず淇℃伅锛氣��'Loading'+鍥炶溅+鎹㈣�屸�濓紝鍏辨樉绀哄寘鎷�鍥炶溅鍜屾崲琛屾帶鍒跺瓧绗﹀湪鍐呯��9涓�瀛楃�︺��

    ! BIOS涓�鏂�0x10鍔熻兘鍙� ah = 0x03锛岃�诲厜鏍囦綅缃�銆�

    ! 杈撳叆锛�bh = 椤靛彿

    ! 杩斿洖锛�ch = 鎵�鎻忓紑濮嬬嚎锛�cl = 鎵�鎻忕粨鏉熺嚎锛�dh = 琛屽彿(0x00椤剁��)锛�dl = 鍒楀彿(0x00鏈�宸﹁竟)銆�

    !

    ! BIOS涓�鏂�0x10鍔熻兘鍙� ah = 0x13锛屾樉绀哄瓧绗︿覆銆�

    ! 杈撳叆锛�al = 鏀剧疆鍏夋爣鐨勬柟寮忓強瑙勫畾灞炴�с��0x01-琛ㄧず浣跨敤bl涓�鐨勫睘鎬у�硷紝鍏夋爣鍋滃湪瀛楃�︿覆缁撳熬澶勩��

    ! es:bp 姝ゅ瘎瀛樺櫒瀵规寚鍚戣�佹樉绀虹殑瀛楃�︿覆璧峰�嬩綅缃�澶勩��cx = 鏄剧ず鐨勫瓧绗︿覆瀛楃�︽暟銆�bh = 鏄剧ず椤甸潰鍙凤紱

    ! bl = 瀛楃�﹀睘鎬с��dh = 琛屽彿锛�dl = 鍒楀彿銆�

153

154         mov     ah,#0x03           ! read cursor pos

155         xor     bh,bh              ! 棣栧厛璇诲厜鏍囦綅缃�銆傝繑鍥炲厜鏍囦綅缃�鍊煎湪dx涓�銆�

156         int     0x10               ! dh - 琛岋紙0--24锛夛紱dl - 鍒�(0--79)銆�

157        

158         mov     cx,#9              ! 鍏辨樉绀�9涓�瀛楃�︺��

159         mov     bx,#0x0007         ! page 0, attribute 7 (normal)

160         mov     bp,#msg1           ! es:bp鎸囧悜瑕佹樉绀虹殑瀛楃�︿覆銆�

161         mov     ax,#0x1301         ! write string, move cursor

162         int     0x10               ! 鍐欏瓧绗︿覆骞剁Щ鍔ㄥ厜鏍囧埌涓茬粨灏惧�勩��

163

164 ! ok, we've written the message, now

165 ! we want to load the system (at 0x10000)

    ! 鐜板湪寮�濮嬪皢system妯″潡鍔犺浇鍒�0x10000锛�64KB锛夊紑濮嬪�勩��

166

167         mov     ax,#SYSSEG

168         mov     es,ax              ! segment of 0x010000 ! es = 瀛樻斁system鐨勬�靛湴鍧�銆�

169         call    read_it            ! 璇荤�佺洏涓�system妯″潡锛�es涓鸿緭鍏ュ弬鏁般��

170         call    kill_motor         ! 鍏抽棴椹卞姩鍣ㄩ┈杈撅紝杩欐牱灏卞彲浠ョ煡閬撻┍鍔ㄥ櫒鐨勭姸鎬佷簡銆�

171         call    print_nl           ! 鍏夋爣鍥炶溅鎹㈣�屻��

172

173 ! After that we check which root-device to use. If the device is

174 ! defined (!= 0), nothing is done and the given device is used.

175 ! Otherwise, either /dev/PS0 (2,28) or /dev/at0 (2,8), depending

176 ! on the number of sectors that the BIOS reports currently.

    ! 姝ゅ悗锛屾垜浠�妫�鏌ヨ�佷娇鐢ㄥ摢涓�鏍规枃浠剁郴缁熻�惧�囷紙绠�绉版牴璁惧�囷級銆傚�傛灉宸茬粡鎸囧畾浜嗚�惧��(!=0)锛�

    ! 灏辩洿鎺ヤ娇鐢ㄧ粰瀹氱殑璁惧�囥�傚惁鍒欏氨闇�瑕佹牴鎹�BIOS鎶ュ憡鐨勬瘡纾侀亾鎵囧尯鏁版潵纭�瀹氬埌搴曚娇鐢�/dev/PS0

    ! (2,28)锛岃繕鏄� /dev/at0 (2,8)銆�

    !! 涓婇潰涓�琛屼腑涓や釜璁惧�囨枃浠剁殑鍚�涔夛細

    !! 鍦�Linux涓�杞�椹辩殑涓昏�惧�囧彿鏄�2(鍙傝�佺��43琛岀殑娉ㄩ噴)锛屾�¤�惧�囧�� = type*4 + nr锛屽叾涓�

    !! nr涓�0-3鍒嗗埆瀵瑰簲杞�椹�A銆�B銆�C鎴�D锛�type鏄�杞�椹辩殑绫诲瀷锛�2脿1.2MB鎴�7脿1.44MB绛夛級銆�

    !! 鍥犱负7*4 + 0 = 28锛屾墍浠� /dev/PS0 (2,28)鎸囩殑鏄�1.44MB A椹卞姩鍣�,鍏惰�惧�囧彿鏄�0x021c

    !! 鍚岀悊 /dev/at0 (2,8)鎸囩殑鏄�1.2MB A椹卞姩鍣�锛屽叾璁惧�囧彿鏄�0x0208銆�

 

    ! 涓嬮潰root_dev瀹氫箟鍦ㄥ紩瀵兼墖鍖�508锛�509瀛楄妭澶勶紝鎸囨牴鏂囦欢绯荤粺鎵�鍦ㄨ�惧�囧彿銆�0x0306鎸囩��2

    ! 涓�纭�鐩樼��1涓�鍒嗗尯銆傝繖閲岄粯璁や负0x0306鏄�鍥犱负褰撴�� Linus 寮�鍙�Linux绯荤粺鏃舵槸鍦ㄧ��2涓�纭�

    ! 鐩樼��1涓�鍒嗗尯涓�瀛樻斁鏍规枃浠剁郴缁熴�傝繖涓�鍊奸渶瑕佹牴鎹�浣犺嚜宸辨牴鏂囦欢绯荤粺鎵�鍦ㄧ‖鐩樺拰鍒嗗尯杩涜�屼��

    ! 鏀广�備緥濡傦紝濡傛灉浣犵殑鏍规枃浠剁郴缁熷湪绗�1涓�纭�鐩樼殑绗�1涓�鍒嗗尯涓婏紝閭ｄ箞璇ュ�煎簲璇ヤ负0x0301锛屽嵆

    ! 锛�0x01, 0x03锛夈�傚�傛灉鏍规枃浠剁郴缁熸槸鍦ㄧ��2涓�Bochs杞�鐩樹笂锛岄偅涔堣�ュ�煎簲璇ヤ负0x021D锛屽嵆

    ! 锛�0x1D,0x02锛夈�傚綋缂栬瘧鍐呮牳鏃讹紝浣犲彲浠ュ湪Makefile鏂囦欢涓�鍙﹁�屾寚瀹氫綘鑷�宸辩殑鍊硷紝鍐呮牳鏄犲儚

    ! 鏂囦欢Image鐨勫垱寤虹▼搴�tools/build浼氫娇鐢ㄤ綘鎸囧畾鐨勫�兼潵璁剧疆浣犵殑鏍规枃浠剁郴缁熸墍鍦ㄨ�惧�囧彿銆�

177

178         seg cs

179         mov     ax,root_dev        ! 鍙�508,509瀛楄妭澶勭殑鏍硅�惧�囧彿骞跺垽鏂�鏄�鍚﹀凡琚�瀹氫箟銆�

180         or      ax,ax

181         jne     root_defined

    ! 鍙栦笂闈㈢��148琛屼繚瀛樼殑姣忕�侀亾鎵囧尯鏁般�傚�傛��sectors=15鍒欒�存槑鏄�1.2MB鐨勯┍鍔ㄥ櫒锛涘�傛��

    ! sectors=18锛屽垯璇存槑鏄�1.44MB杞�椹便�傚洜涓烘槸鍙�寮曞�肩殑椹卞姩鍣�锛屾墍浠ヨ偗瀹氭槸A椹便��

182         seg cs

183         mov     bx,sectors

184         mov     ax,#0x0208         ! /dev/ps0 - 1.2Mb

185         cmp     bx,#15             ! 鍒ゆ柇姣忕�侀亾鎵囧尯鏁版槸鍚�=15

186         je      root_defined       ! 濡傛灉绛変簬锛屽垯ax涓�灏辨槸寮曞�奸┍鍔ㄥ櫒鐨勮�惧�囧彿銆�

187         mov     ax,#0x021c         ! /dev/PS0 - 1.44Mb

188         cmp     bx,#18

189         je      root_defined

190 undef_root:                        ! 濡傛灉閮戒笉涓�鏍凤紝鍒欐�诲惊鐜�锛堟�绘満锛夈��

191         jmp undef_root

192 root_defined:

193         seg cs

194         mov     root_dev,ax        ! 灏嗘��鏌ヨ繃鐨勮�惧�囧彿淇濆瓨鍒�root_dev涓�銆�

195

196 ! after that (everyting loaded), we jump to

197 ! the setup-routine loaded directly after

198 ! the bootblock:

    ! 鍒版�わ紝鎵�鏈夌▼搴忛兘鍔犺浇瀹屾瘯锛屾垜浠�灏辫烦杞�鍒拌��鍔犺浇鍦�bootsect鍚庨潰鐨�setup绋嬪簭鍘汇��

    ! 涓嬮潰娈甸棿璺宠浆鎸囦护锛�Jump Intersegment锛夈�傝烦杞�鍒�0x9020:0000(setup.s绋嬪簭寮�濮嬪��)鍘绘墽琛屻��

199

200         jmpi    0,SETUPSEG         !!!! 鍒版�ゆ湰绋嬪簭灏辩粨鏉熶簡銆�!!!!

 

    ! 涓嬮潰鏄�鍑犱釜瀛愮▼搴忋��read_it鐢ㄤ簬璇诲彇纾佺洏涓婄殑system妯″潡銆�kill_moter鐢ㄤ簬鍏抽棴杞�椹遍┈杈俱��

    ! 杩樻湁涓�浜涘睆骞曟樉绀哄瓙绋嬪簭銆�

201

202 ! This routine loads the system at address 0x10000, making sure

203 ! no 64kB boundaries are crossed. We try to load it as fast as

204 ! possible, loading whole tracks whenever we can.

205 !

206 ! in:   es - starting address segment (normally 0x1000)

207 !

    ! 璇ュ瓙绋嬪簭灏嗙郴缁熸ā鍧楀姞杞藉埌鍐呭瓨鍦板潃0x10000澶勶紝骞剁‘瀹氭病鏈夎法瓒�64KB鐨勫唴瀛樿竟鐣屻��

    ! 鎴戜滑璇曞浘灏藉揩鍦拌繘琛屽姞杞斤紝鍙�瑕佸彲鑳斤紝灏辨瘡娆″姞杞芥暣鏉＄�侀亾鐨勬暟鎹�銆�

    ! 杈撳叆锛�es 鈥� 寮�濮嬪唴瀛樺湴鍧�娈靛�硷紙閫氬父鏄�0x1000锛�

    !

    ! 涓嬮潰浼�鎿嶄綔绗�.word瀹氫箟涓�涓�2瀛楄妭鐩�鏍囥�傜浉褰撲簬C璇�瑷�绋嬪簭涓�瀹氫箟鐨勫彉閲忓拰鎵�鍗犲唴瀛樼┖闂村ぇ灏忋��

    ! '1+SETUPLEN'琛ㄧず寮�濮嬫椂宸茬粡璇昏繘1涓�寮曞�兼墖鍖哄拰setup绋嬪簭鎵�鍗犵殑鎵囧尯鏁�SETUPLEN銆�

208 sread:  .word 1+SETUPLEN        ! sectors read of current track !褰撳墠纾侀亾涓�宸茶�绘墖鍖烘暟銆�

209 head:   .word 0                 ! current head    !褰撳墠纾佸ご鍙枫��

210 track:  .word 0                 ! current track   !褰撳墠纾侀亾鍙枫��

211

212 read_it:

    ! 棣栧厛娴嬭瘯杈撳叆鐨勬�靛�笺�備粠鐩樹笂璇诲叆鐨勬暟鎹�蹇呴』瀛樻斁鍦ㄤ綅浜庡唴瀛樺湴鍧� 64KB 鐨勮竟鐣屽紑濮嬪�勶紝鍚﹀��

    ! 杩涘叆姝诲惊鐜�銆傛竻bx瀵勫瓨鍣�锛岀敤浜庤〃绀哄綋鍓嶆�靛唴瀛樻斁鏁版嵁鐨勫紑濮嬩綅缃�銆�

    ! 153琛屼笂鐨勬寚浠�test浠ユ瘮鐗逛綅閫昏緫涓庝袱涓�鎿嶄綔鏁般�傝嫢涓や釜鎿嶄綔鏁板�瑰簲鐨勬瘮鐗逛綅閮戒��1锛屽垯缁撴灉

    ! 鍊肩殑瀵瑰簲姣旂壒浣嶄负1锛屽惁鍒欎负0銆傝�ユ搷浣滅粨鏋滃彧褰卞搷鏍囧織锛堥浂鏍囧��ZF绛夛級銆備緥濡傝嫢AX=0x1000锛�

    ! 閭ｄ箞test鎸囦护鐨勬墽琛岀粨鏋滄槸(0x1000 & 0x0fff) = 0x0000锛屼簬鏄�ZF鏍囧織缃�浣嶃�傛�ゆ椂鍗充笅涓�鏉�

    ! 鎸囦护jne 鏉′欢涓嶆垚绔嬨��

213         mov ax,es

214         test ax,#0x0fff

215 die:    jne die                 ! es must be at 64kB boundary ! es鍊煎繀椤讳綅浜�64KB杈圭晫!

216         xor bx,bx               ! bx is starting address within segment! bx涓烘�靛唴鍋忕Щ銆�

217 rp_read:

    ! 鎺ョ潃鍒ゆ柇鏄�鍚﹀凡缁忚�诲叆鍏ㄩ儴鏁版嵁銆傛瘮杈冨綋鍓嶆墍璇绘�垫槸鍚﹀氨鏄�绯荤粺鏁版嵁鏈�绔�鎵�澶勭殑娈�(#ENDSEG)锛�

    ! 濡傛灉涓嶆槸灏辫烦杞�鑷充笅闈�ok1_read鏍囧彿澶勭户缁�璇绘暟鎹�銆傚惁鍒欓��鍑哄瓙绋嬪簭杩斿洖銆�

218         mov ax,es

219         cmp ax,#ENDSEG          ! have we loaded all yet?    ! 鏄�鍚﹀凡缁忓姞杞戒簡鍏ㄩ儴鏁版嵁锛�

220         jb ok1_read

221         ret

222 ok1_read:

    ! 鐒跺悗璁＄畻鍜岄獙璇佸綋鍓嶇�侀亾闇�瑕佽�诲彇鐨勬墖鍖烘暟锛屾斁鍦�ax瀵勫瓨鍣ㄤ腑銆�

    ! 鏍规嵁褰撳墠纾侀亾杩樻湭璇诲彇鐨勬墖鍖烘暟浠ュ強娈靛唴鏁版嵁瀛楄妭寮�濮嬪亸绉讳綅缃�锛岃�＄畻濡傛灉鍏ㄩ儴璇诲彇杩欎簺鏈�璇�

    ! 鎵囧尯锛屾墍璇绘�诲瓧鑺傛暟鏄�鍚︿細瓒呰��64KB娈甸暱搴︾殑闄愬埗銆傝嫢浼氳秴杩囷紝鍒欐牴鎹�姝ゆ�℃渶澶氳兘璇诲叆鐨勫瓧鑺�

    ! 鏁� (64KB 鈥�娈靛唴鍋忕Щ浣嶇疆)锛屽弽绠楀嚭姝ゆ�￠渶瑕佽�诲彇鐨勬墖鍖烘暟銆�

223         seg cs

224         mov ax,sectors             ! 鍙栨瘡纾侀亾鎵囧尯鏁般��

225         sub ax,sread               ! 鍑忓幓褰撳墠纾侀亾宸茶�绘墖鍖烘暟銆�

226         mov cx,ax                  ! cx = ax = 褰撳墠纾侀亾鏈�璇绘墖鍖烘暟銆�

227         shl cx,#9                  ! cx = cx * 512 瀛楄妭 + 娈靛唴褰撳墠鍋忕Щ鍊�(bx)銆�

228         add cx,bx                  !   = 姝ゆ�¤�绘搷浣滃悗锛屾�靛唴鍏辫�诲叆鐨勫瓧鑺傛暟銆�

229         jnc ok2_read               ! 鑻ユ病鏈夎秴杩�64KB瀛楄妭锛屽垯璺宠浆鑷�ok2_read澶勬墽琛屻��

230         je ok2_read

    ! 鑻ュ姞涓婃�ゆ�″皢璇荤�侀亾涓婃墍鏈夋湭璇绘墖鍖烘椂浼氳秴杩�64KB锛屽垯璁＄畻姝ゆ椂鏈�澶氳兘璇诲叆鐨勫瓧鑺傛暟锛�

    ! (64KB鈥�娈靛唴璇诲亸绉讳綅缃�)锛屽啀杞�鎹㈡垚闇�璇诲彇鐨勬墖鍖烘暟銆傚叾涓�0鍑忔煇鏁板氨鏄�鍙栬�ユ暟64KB鐨勮ˉ鍊笺��

231         xor ax,ax

232         sub ax,bx

233         shr ax,#9

234 ok2_read:

    ! 璇诲綋鍓嶇�侀亾涓婃寚瀹氬紑濮嬫墖鍖猴紙cl锛夊拰闇�璇绘墖鍖烘暟锛�al锛夌殑鏁版嵁鍒� es:bx寮�濮嬪�勩�傜劧鍚庣粺璁″綋鍓�

    ! 纾侀亾涓婂凡缁忚�诲彇鐨勬墖鍖烘暟骞朵笌纾侀亾鏈�澶ф墖鍖烘暟 sectors浣滄瘮杈冦�傚�傛灉灏忎��sectors璇存槑褰撳墠纾�

    ! 閬撲笂鐨勮繕鏈夋墖鍖烘湭璇汇�備簬鏄�璺宠浆鍒�ok3_read澶勭户缁�鎿嶄綔銆�

235         call read_track            ! 璇诲綋鍓嶇�侀亾涓婃寚瀹氬紑濮嬫墖鍖哄拰闇�璇绘墖鍖烘暟鐨勬暟鎹�銆�

236         mov cx,ax                  ! cx = 璇ユ�℃搷浣滃凡璇诲彇鐨勬墖鍖烘暟銆�

237         add ax,sread               ! 鍔犱笂褰撳墠纾侀亾涓婂凡缁忚�诲彇鐨勬墖鍖烘暟銆�

238         seg cs

239         cmp ax,sectors             ! 鑻ュ綋鍓嶇�侀亾涓婄殑杩樻湁鎵囧尯鏈�璇伙紝鍒欒烦杞�鍒�ok3_read澶勩��

240         jne ok3_read

    ! 鑻ヨ�ョ�侀亾鐨勫綋鍓嶇�佸ご闈㈡墍鏈夋墖鍖哄凡缁忚�诲彇锛屽垯璇昏�ョ�侀亾鐨勪笅涓�纾佸ご闈�锛�1鍙风�佸ご锛変笂鐨勬暟鎹�銆�

    ! 濡傛灉宸茬粡瀹屾垚锛屽垯鍘昏�讳笅涓�纾侀亾銆�

241         mov ax,#1

242         sub ax,head                ! 鍒ゆ柇褰撳墠纾佸ご鍙枫��

243         jne ok4_read               ! 濡傛灉鏄�0纾佸ご锛屽垯鍐嶅幓璇�1纾佸ご闈�涓婄殑鎵囧尯鏁版嵁銆�

244         inc track                  ! 鍚﹀垯鍘昏�讳笅涓�纾侀亾銆�

245 ok4_read:

246         mov head,ax                ! 淇濆瓨褰撳墠纾佸ご鍙枫��

247         xor ax,ax                  ! 娓呭綋鍓嶇�侀亾宸茶�绘墖鍖烘暟銆�

248 ok3_read:

    ! 濡傛灉褰撳墠纾侀亾涓婄殑杩樻湁鏈�璇绘墖鍖猴紝鍒欓�栧厛淇濆瓨褰撳墠纾侀亾宸茶�绘墖鍖烘暟锛岀劧鍚庤皟鏁村瓨鏀炬暟鎹�澶勭殑寮�

    ! 濮嬩綅缃�銆傝嫢灏忎簬64KB杈圭晫鍊硷紝鍒欒烦杞�鍒�rp_read(217琛�)澶勶紝缁х画璇绘暟鎹�銆�

249         mov sread,ax               ! 淇濆瓨褰撳墠纾侀亾宸茶�绘墖鍖烘暟銆�

250         shl cx,#9                  ! 涓婃�″凡璇绘墖鍖烘��*512瀛楄妭銆�

251         add bx,cx                  ! 璋冩暣褰撳墠娈靛唴鏁版嵁寮�濮嬩綅缃�銆�

252         jnc rp_read

    ! 鍚﹀垯璇存槑宸茬粡璇诲彇64KB鏁版嵁銆傛�ゆ椂璋冩暣褰撳墠娈碉紝涓鸿�讳笅涓�娈垫暟鎹�浣滃噯澶囥��

253         mov ax,es

254         add ah,#0x10               ! 灏嗘�靛熀鍧�璋冩暣涓烘寚鍚戜笅涓�涓�64KB鍐呭瓨寮�濮嬪�勩��

255         mov es,ax

256         xor bx,bx                  ! 娓呮�靛唴鏁版嵁寮�濮嬪亸绉诲�笺��

257         jmp rp_read                ! 璺宠浆鑷�rp_read(217琛�)澶勶紝缁х画璇绘暟鎹�銆�

258

    ! read_track 瀛愮▼搴忋�傝�诲綋鍓嶇�侀亾涓婃寚瀹氬紑濮嬫墖鍖哄拰闇�璇绘墖鍖烘暟鐨勬暟鎹�鍒� es:bx 寮�濮嬪�勩�傚弬瑙�

    ! 绗�67琛屼笅瀵�BIOS纾佺洏璇讳腑鏂�int 0x13锛�ah=2鐨勮�存槑銆�

    ! al 鈥� 闇�璇绘墖鍖烘暟锛�es:bx 鈥� 缂撳啿鍖哄紑濮嬩綅缃�銆�

259 read_track:

    ! 棣栧厛璋冪敤BIOS涓�鏂�0x10锛屽姛鑳�0x0e锛堜互鐢典紶鏂瑰紡鍐欏瓧绗︼級锛屽厜鏍囧墠绉讳竴浣嶇疆銆傛樉绀轰竴涓�'.'銆�

260         pusha                      ! 鍘嬪叆鎵�鏈夊瘎瀛樺櫒锛�push all锛夈��

261         pusha                      ! 涓鸿皟鐢ㄦ樉绀轰腑鏂�鍘嬪叆鎵�鏈夊瘎瀛樺櫒鍊笺��

262         mov ax, #0xe2e             ! loading... message 2e = .

263         mov bx, #7                 ! 瀛楃�﹀墠鏅�鑹插睘鎬с��

264         int 0x10

265         popa           

266

    ! 鐒跺悗姝ｅ紡杩涜�岀�侀亾鎵囧尯璇绘搷浣溿��

267         mov dx,track               ! 鍙栧綋鍓嶇�侀亾鍙枫��

268         mov cx,sread               ! 鍙栧綋鍓嶇�侀亾涓婂凡璇绘墖鍖烘暟銆�

269         inc cx                     ! cl = 寮�濮嬭�绘墖鍖恒��

270         mov ch,dl                  ! ch = 褰撳墠纾侀亾鍙枫��

271         mov dx,head                ! 鍙栧綋鍓嶇�佸ご鍙枫��

272         mov dh,dl                  ! dh = 纾佸ご鍙凤紝dl = 椹卞姩鍣ㄥ彿(涓�0琛ㄧず褰撳墠A椹卞姩鍣�)銆�

273         and dx,#0x0100             ! 纾佸ご鍙蜂笉澶т簬1銆�

274         mov ah,#2                  ! ah = 2锛岃�荤�佺洏鎵囧尯鍔熻兘鍙枫��

275        

276         push dx                    ! save for error dump

277         push cx                    ! 涓哄嚭閿欐儏鍐典繚瀛樹竴浜涗俊鎭�銆�

278         push bx

279         push ax

280

281         int 0x13

282         jc bad_rt                  ! 鑻ュ嚭閿欙紝鍒欒烦杞�鑷�bad_rt銆�

283         add sp,#8                  ! 娌℃湁鍑洪敊銆傚洜姝や涪寮冧负鍑洪敊鎯呭喌淇濆瓨鐨勪俊鎭�銆�

284         popa

285         ret

286

    ! 璇荤�佺洏鎿嶄綔鍑洪敊銆傚垯鍏堟樉绀哄嚭閿欎俊鎭�锛岀劧鍚庢墽琛岄┍鍔ㄥ櫒澶嶄綅鎿嶄綔锛堢�佺洏涓�鏂�鍔熻兘鍙�0锛夛紝鍐嶈烦杞�

    ! 鍒�read_track澶勯噸璇曘��

287 bad_rt: push ax                    ! save error code

288         call print_all             ! ah = error, al = read

289        

290        

291         xor ah,ah

292         xor dl,dl

293         int 0x13

294        

295

296         add sp, #10                ! 涓㈠純涓哄嚭閿欐儏鍐典繚瀛樼殑淇℃伅銆�

297         popa   

298         jmp read_track

299

300 /*

301  *      print_all is for debugging purposes. 

302  *      It will print out all of the registers.  The assumption is that this is

303  *      called from a routine, with a stack frame like

304  *      dx

305  *      cx

306  *      bx

307  *      ax

308  *      error

309  *      ret <- sp

310  *

311 */

    /*

     *      瀛愮▼搴�print_all鐢ㄤ簬璋冭瘯鐩�鐨勩�傚畠浼氭樉绀烘墍鏈夊瘎瀛樺櫒鐨勫唴瀹广�傚墠鎻愭潯浠舵槸闇�瑕佷粠

     *      涓�涓�瀛愮▼搴忎腑璋冪敤锛屽苟涓旀爤甯х粨鏋勪负濡備笅鎵�绀猴細锛堣�佷笂闈�锛�

     */

    ! 鑻ユ爣蹇楀瘎瀛樺櫒鐨�CF=0锛屽垯涓嶆樉绀哄瘎瀛樺櫒鍚嶇О銆�

312 

313 print_all:

314         mov cx, #5                 ! error code + 4 registers  ! 鏄剧ず鍊间釜鏁般��

315         mov bp, sp                 ! 淇濆瓨褰撳墠鏍堟寚閽�sp銆�

316

317 print_loop:

318         push cx                    ! save count left   ! 淇濆瓨闇�瑕佹樉绀虹殑鍓╀綑涓�鏁般��

319         call print_nl              ! nl for readability  ! 涓哄彲璇绘�у厛璁╁厜鏍囧洖杞︽崲琛屻��

320         jae no_reg                 ! see if register name is needed

321                                    ! 鑻�FLAGS鐨勬爣蹇�CF=0鍒欎笉鏄剧ず瀵勫瓨鍣ㄥ悕锛屼簬鏄�璺宠浆銆�

    ! 瀵瑰簲鍏ユ爤瀵勫瓨鍣ㄩ『搴忓垎鍒�鏄剧ず瀹冧滑鐨勫悕绉扳��AX锛氣�濈瓑銆�

322         mov ax, #0xe05 + 0x41 - 1  ! ah =鍔熻兘鍙凤紙0x0e锛夛紱al =瀛楃�︼��0x05 + 0x41 -1锛夈��

323         sub al, cl

324         int 0x10

325

326         mov al, #0x58              ! X     ! 鏄剧ず瀛楃��'X'銆�

327         int 0x10

328

329         mov al, #0x3a              ! :     ! 鏄剧ず瀛楃��':'銆�

330         int 0x10

331

    ! 鏄剧ず瀵勫瓨鍣�bp鎵�鎸囨爤涓�鍐呭�广�傚紑濮嬫椂bp鎸囧悜杩斿洖鍦板潃銆�

332 no_reg:

333         add bp, #2                 ! next register   ! 鏍堜腑涓嬩竴涓�浣嶇疆銆�

334         call print_hex             ! print it        ! 浠ュ崄鍏�杩涘埗鏄剧ず銆�

335         pop cx

336         loop print_loop

337         ret

338

    ! 璋冪敤BIOS涓�鏂�0x10锛屼互鐢典紶鏂瑰紡鏄剧ず鍥炶溅鎹㈣�屻��

339 print_nl:

340         mov ax, #0xe0d             ! CR

341         int 0x10

342         mov al, #0xa               ! LF

343         int 0x10

344         ret

345

346 /*

347  *      print_hex is for debugging purposes, and prints the word

348  *      pointed to by ss:bp in hexadecmial.

349 */

    /*

     *      瀛愮▼搴�print_hex鐢ㄤ簬璋冭瘯鐩�鐨勩�傚畠浣跨敤鍗佸叚杩涘埗鍦ㄥ睆骞曚笂鏄剧ず鍑�

     *      ss:bp鎸囧悜鐨勫瓧銆�

     */

350

    ! 璋冪敤BIOS涓�鏂�0x10锛屼互鐢典紶鏂瑰紡鍜�4涓�鍗佸叚杩涘埗鏁版樉绀�ss:bp鎸囧悜鐨勫瓧銆�

351 print_hex:

352         mov     cx, #4             ! 4 hex digits         ! 瑕佹樉绀�4涓�鍗佸叚杩涘埗鏁板瓧銆�

353         mov     dx, (bp)           ! load word into dx    ! 鏄剧ず鍊兼斁鍏�dx涓�銆�

354 print_digit:

    ! 鍏堟樉绀洪珮瀛楄妭锛屽洜姝ら渶瑕佹妸dx涓�鍊煎乏鏃�4姣旂壒锛屾�ゆ椂楂�4姣旂壒鍦�dx鐨勪綆4浣嶄腑銆�

355         rol     dx, #4             ! rotate so that lowest 4 bits are used

356         mov     ah, #0xe           ! 涓�鏂�鍔熻兘鍙枫��

357         mov     al, dl             ! mask off so we have only next nibble

358         and     al, #0xf           ! 鏀惧叆al涓�骞跺彧鍙栦��4姣旂壒锛�1涓�鍊硷級銆�

    ! 鍔犱笂'0' 鐨�ASCII鐮佸��0x30锛屾妸鏄剧ず鍊艰浆鎹㈡垚鍩轰簬鏁板瓧'0' 鐨勫瓧绗︺�傝嫢姝ゆ椂al 鍊艰秴杩� 0x39锛�

    ! 琛ㄧず娆叉樉绀哄�艰秴杩囨暟瀛�9锛屽洜姝ら渶瑕佷娇鐢�'A'--'F'鏉ヨ〃绀恒��

359         add     al, #0x30          ! convert to 0 based digit, '0'

360         cmp     al, #0x39          ! check for overflow

361         jbe     good_digit

362         add     al, #0x41 - 0x30 - 0xa       ! 'A' - '0' - 0xa

363

364 good_digit:

365         int     0x10

366         loop    print_digit        ! cx--銆傝嫢cx>0鍒欏幓鏄剧ず涓嬩竴涓�鍊笺��

367         ret

368

369

370 /*

371  * This procedure turns off the floppy drive motor, so

372  * that we enter the kernel in a known state, and

373  * don't have to worry about it later.

374  */

    /* 杩欎釜瀛愮▼搴忕敤浜庡叧闂�杞�椹辩殑椹�杈撅紝杩欐牱鎴戜滑杩涘叆鍐呮牳鍚庡氨鑳�

     * 鐭ラ亾瀹冩墍澶勭殑鐘舵�侊紝浠ュ悗涔熷氨鏃犻』鎷呭績瀹冧簡銆�

     */

    ! 涓嬮潰绗�377琛屼笂鐨勫��0x3f2鏄�杞�鐩樻帶鍒跺櫒鐨勪竴涓�绔�鍙ｏ紝琚�绉颁负鏁板瓧杈撳嚭瀵勫瓨鍣�锛�DOR锛夌��鍙ｃ�傚畠鏄�

    ! 涓�涓�8浣嶇殑瀵勫瓨鍣�锛屽叾浣�7--浣�4鍒嗗埆鐢ㄤ簬鎺у埗4涓�杞�椹憋紙D--A锛夌殑鍚�鍔ㄥ拰鍏抽棴銆備綅3--浣�2鐢ㄤ簬

    ! 鍏佽��/绂佹��DMA鍜屼腑鏂�璇锋眰浠ュ強鍚�鍔�/澶嶄綅杞�鐩樻帶鍒跺��FDC銆� 浣�1--浣�0鐢ㄤ簬閫夋嫨閫夋嫨鎿嶄綔鐨勮蒋椹便��

    ! 绗�378琛屼笂鍦�al涓�璁剧疆骞惰緭鍑虹��0鍊硷紝灏辨槸鐢ㄤ簬閫夋嫨A椹卞姩鍣�锛屽叧闂�FDC锛岀�佹��DMA鍜屼腑鏂�璇锋眰锛�

    ! 鍏抽棴椹�杈俱�傛湁鍏宠蒋椹辨帶鍒跺崱缂栫▼鐨勮�︾粏淇℃伅璇峰弬瑙�kernel/blk_drv/floppy.c绋嬪簭鍚庨潰鐨勮�存槑銆�

375 kill_motor:

376         push dx

377         mov dx,#0x3f2              ! 杞�椹辨帶鍒跺崱鐨勬暟瀛楄緭鍑哄瘎瀛樺櫒绔�鍙ｏ紝鍙�鍐欍��

378         xor al, al                 ! A椹卞姩鍣�锛屽叧闂�FDC锛岀�佹��DMA鍜屼腑鏂�璇锋眰锛屽叧闂�椹�杈俱��

379         outb                       ! 灏�al涓�鐨勫唴瀹硅緭鍑哄��dx鎸囧畾鐨勭��鍙ｅ幓銆�

380         pop dx

381         ret

382

383 sectors:

384         .word 0                    ! 瀛樻斁褰撳墠鍚�鍔ㄨ蒋鐩樻瘡纾侀亾鐨勬墖鍖烘暟銆�

385

386 msg1:                              ! 寮�鏈鸿皟鐢�BIOS涓�鏂�鏄剧ず鐨勪俊鎭�銆傚叡9涓�瀛楃�︺��

387         .byte 13,10                ! 鍥炶溅銆佹崲琛岀殑ASCII鐮併��

388         .ascii "Loading"

389

    ! 琛ㄧず涓嬮潰璇�鍙ヤ粠鍦板潃508(0x1FC)寮�濮嬶紝鎵�浠�root_dev鍦ㄥ惎鍔ㄦ墖鍖虹殑绗�508寮�濮嬬殑2涓�瀛楄妭涓�銆�

390 .org 506

391 swap_dev:

392         .word SWAP_DEV             ! 杩欓噷瀛樻斁浜ゆ崲绯荤粺鎵�鍦ㄨ�惧�囧彿(init/main.c涓�浼氱��)銆�

393 root_dev:

394         .word ROOT_DEV             ! 杩欓噷瀛樻斁鏍规枃浠剁郴缁熸墍鍦ㄨ�惧�囧彿(init/main.c涓�浼氱��)銆�

 

    ! 涓嬮潰鏄�鍚�鍔ㄧ洏鍏锋湁鏈夋晥寮曞�兼墖鍖虹殑鏍囧織銆備粎渚�BIOS涓�鐨勭▼搴忓姞杞藉紩瀵兼墖鍖烘椂璇嗗埆浣跨敤銆傚畠蹇呴』

    ! 浣嶄簬寮曞�兼墖鍖虹殑鏈�鍚庝袱涓�瀛楄妭涓�銆�

395 boot_flag:

396         .word 0xAA55

397

398 .text

399 endtext:

400 .data

401 enddata:

402 .bss

403 endbss:

404