SliTaz Repositories

     1.1 --- a/BootProg/stuff/boot16.asm	Fri Feb 18 22:59:06 2022 +0000
     1.2 +++ b/BootProg/stuff/boot16.asm	Wed Apr 20 15:10:50 2022 +0000
     1.3 @@ -213,14 +213,14 @@
     1.4          mul     bx                      ; dx:ax = 0 = LBA (LBA are relative to FAT)
     1.5          mov     cx, word [bx(bpbSectorsPerFAT)]
     1.6  
     1.7 -        call    ReadCXSectors           ; read fat and clear cx
     1.8 +        call    ReadCXSectors           ; read fat and clear ax & cx
     1.9  
    1.10  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    1.11  ;; load the root directory in ;;
    1.12  ;; its entirety (16KB max)    ;;
    1.13  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    1.14  
    1.15 -        mov     ax, 32
    1.16 +        mov     al, 32
    1.17  
    1.18          mul     word [bx(bpbRootEntries)]
    1.19          div     word [bx(bpbBytesPerSector)]
    1.20 @@ -230,7 +230,7 @@
    1.21          mul     bp                      ; [bx(bpbSectorsPerFAT)], set by ReadCXSectors
    1.22  
    1.23          push    es
    1.24 -        call    ReadCXSectors           ; read root directory, clear cx and di
    1.25 +        call    ReadCXSectors           ; read root directory; clear ax, cx and di
    1.26          pop     es
    1.27  
    1.28  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    1.29 @@ -248,15 +248,15 @@
    1.30  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
    1.31  
    1.32  FindNameCycle:
    1.33 -        cmp     byte [es:di], ch
    1.34 -        je      FindNameFailed          ; end of root directory (NULL entry found)
    1.35          push    di
    1.36          mov     cl, 11
    1.37          mov     si, ProgramName         ; ds:si -> program name
    1.38          repe    cmpsb
    1.39          pop     di
    1.40          je      FindNameFound
    1.41 -        add     di, byte 32
    1.42 +        scasb
    1.43 +        je      FindNameFailed          ; end of root directory (NULL entry found)
    1.44 +        add     di, byte 31
    1.45          dec     word [bx(bpbRootEntries)]
    1.46          jnz     FindNameCycle           ; next root entry
    1.47  
    1.48 @@ -298,28 +298,26 @@
    1.49          jnc     First64
    1.50          mov     ah, (1000h+ImageLoadSeg)>>8 ; adjust segment for 2nd part of FAT16
    1.51  First64:
    1.52 +        mov     dx, 0FFF8h
    1.53 +
    1.54          cmp     [bx(bpbSectorsPerFAT)], cx ; 1..12 = FAT12, 16..256 = FAT16
    1.55          mov     ds, ax
    1.56 -        jbe     ReadClusterFat12
    1.57 +        ja      ReadClusterFat16
    1.58  
    1.59 -        lodsw                           ; ax = next cluster
    1.60 -        cmp     ax, 0FFF8h
    1.61 -        jmp     short	ReadClusterDone
    1.62 -
    1.63 -ReadClusterFat12:
    1.64 +        mov     dh, 0Fh
    1.65          add     si, [cs:di]
    1.66          shr     si, 1                   ; si = cluster * 3 / 2
    1.67  
    1.68 +ReadClusterFat16:
    1.69          lodsw                           ; ax = next cluster
    1.70          jnc     ReadClusterEven
    1.71  
    1.72          rol     ax, cl
    1.73  
    1.74  ReadClusterEven:
    1.75 -        and     ax, 0FFFh               ; mask cluster value
    1.76 -        cmp     ax, 0FF8h
    1.77 +        and     ah, dh                  ; mask cluster value
    1.78 +        cmp     ax, dx
    1.79  
    1.80 -ReadClusterDone:
    1.81          push    cs
    1.82          pop     ds
    1.83          inc     di
    1.84 @@ -352,7 +350,7 @@
    1.85          add     ax, bp                  ; LBA for cluster data
    1.86          adc     dx, bx                  ; dx:ax = LBA
    1.87  
    1.88 -        call    ReadSector              ; clear cx
    1.89 +        call    ReadSector              ; clear ax & cx, restore dx
    1.90  
    1.91          jne     ReadClusters
    1.92  
    1.93 @@ -365,7 +363,6 @@
    1.94          mov     ds, bp                  ; bp=ds=seg the file is loaded to
    1.95  
    1.96          add     bp, [bx+08h]            ; bp = image base
    1.97 -        mov     ax, [bx+06h]            ; ax = reloc items
    1.98          mov     di, [bx+18h]            ; di = reloc table pointer
    1.99  
   1.100          cmp     word [bx], 5A4Dh        ; "MZ" signature?
   1.101 @@ -374,19 +371,22 @@
   1.102  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.103  ;; Setup and run a .COM program ;;
   1.104  ;; Set CS=DS=ES=SS SP=0 IP=100h ;;
   1.105 +;; AX=0ffffh BX=0 CX=0 DX=drive ;;
   1.106 +;; and cmdline=void             ;;
   1.107  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.108  
   1.109 +        mov     di, 100h                ; ip
   1.110          mov     bp, ImageLoadSeg-10h    ; "org 100h" stuff :)
   1.111          mov     ss, bp
   1.112          xor     sp, sp
   1.113          push    bp                      ; cs, ds and es
   1.114 -        mov     bh, 1                   ; ip
   1.115          jmp     short Run
   1.116  
   1.117  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.118  ;; Relocate, setup and run a .EXE program     ;;
   1.119  ;; Set CS:IP, SS:SP, DS, ES and AX according  ;;
   1.120  ;; to wiki.osdev.org/MZ#Initial_Program_State ;;
   1.121 +;; AX=0ffffh BX=0 CX=0 DX=drive cmdline=void  ;;
   1.122  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.123  
   1.124  ReloCycle:
   1.125 @@ -397,8 +397,8 @@
   1.126          scasw                           ; point to next entry
   1.127  
   1.128  RelocateEXE:
   1.129 -        dec     ax                      ; 32768 max (128KB table)
   1.130 -        jns     ReloCycle               ; leave with ax=0ffffh: both FCB in the
   1.131 +        dec     word [bx+06h]           ; reloc items, 32768 max (128KB table)
   1.132 +        jns     ReloCycle
   1.133                                          ; PSP don't have a valid drive identifier
   1.134          les     si, [bx+0Eh]
   1.135          add     si, bp
   1.136 @@ -409,13 +409,15 @@
   1.137          push    si                      ; containing the PSP structure
   1.138  
   1.139          add     bp, [bx+16h]            ; cs for EXE
   1.140 -        mov     bx, [bx+14h]            ; ip for EXE
   1.141 +        mov     di, [bx+14h]            ; ip for EXE
   1.142  Run:
   1.143          pop     ds
   1.144          push    bp
   1.145 -        push    bx
   1.146 +        push    di
   1.147          push    ds
   1.148          pop     es
   1.149 +        mov     [80h], ax               ; clear cmdline
   1.150 +        dec     ax                      ; both FCB in the PSP don't have a valid drive identifier
   1.151  
   1.152  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.153  ;; Set the magic numbers so the program knows that it   ;;
   1.154 @@ -539,10 +541,17 @@
   1.155          dec     di                      ; keep C
   1.156          loopne  ReadSectorNext          ; until cluster sector count or file sector count is reached
   1.157          pop     si
   1.158 +        mov     ax, bx                  ; clear ax
   1.159          mov     dx, [bx]                ; pass the BIOS boot drive to Run or Error
   1.160  
   1.161          ret
   1.162  
   1.163 +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.164 +;; Fill free space with zeroes ;;
   1.165 +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.166 +
   1.167 +                times (512-13-20-($-$$)) db 0
   1.168 +
   1.169  ;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.170  ;; Error Messaging Code ;;
   1.171  ;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.172 @@ -566,12 +575,6 @@
   1.173          hlt
   1.174          jmp     short Stop
   1.175  
   1.176 -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.177 -;; Fill free space with zeroes ;;
   1.178 -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.179 -
   1.180 -                times (512-13-($-$$)) db 0
   1.181 -
   1.182  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   1.183  ;; Name of the file to load and run ;;
   1.184  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;