Make it actually boot on M-systems flash...

diff --git a/ldlinux.asm b/ldlinux.asm
index af70d77..41c31ec 100644 (file)
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -56,7 +56,9 @@ syslinux_id   equ 031h                ; SYSLINUX (3) version 1.x (1)
 ; hog some of high memory.  Therefore, we load it at 7000:0000h and copy
 ; it before starting the Linux kernel.
 ;
-real_mode_seg  equ 5000h
+real_mode_seg  equ 7000h
+fake_setup_seg equ real_mode_seg+020h
+
                struc real_mode_seg_t
                resb 20h-($-$$)         ; org 20h
 kern_cmd_magic resw 1                  ; Magic # for command line
@@ -1927,13 +1929,13 @@ is_mem_cmd:
                 add si,byte 4
                 call parseint
                jc skip_this_opt                ; Not an integer
-               mov [ss:HighMemSize],ebx
+               mov [cs:HighMemSize],ebx
                jmp short skip_this_opt
 cmdline_end:
-                push ss                         ; Restore standard DS
+                push cs                         ; Restore standard DS
                 pop ds
-               sub di,cmd_line_here
-               mov [CmdLineLen],di             ; Length including final null
+               sub si,cmd_line_here
+               mov [CmdLineLen],si             ; Length including final null
 ;
 ; Now check if we have a large kernel, which needs to be loaded high
 ;
@@ -2035,7 +2037,7 @@ read_kernel:
                 mov [HiLoadAddr],ecx
                sub ecx,100000h                 ; Turn into a counter
                shr ecx,2                       ; Convert to dwords
-               add esi,90000h                  ; Pointer to source
+               add esi,(real_mode_seg << 4)    ; Pointer to source
                 mov edi,100000h                 ; Copy to address 100000h
                 call bcopy                     ; Transfer to high memory
 ;
@@ -2078,6 +2080,16 @@ high_load_done:
 ;
                 call abort_check               ; Last chance!!
 
+               mov si,ready_msg
+               call cwritestr
+;
+; Now, if we were supposed to load "low", copy the kernel down to 10000h
+; and the real mode stuff to 90000h.  We assume that all bzImage kernels are
+; capable of starting their setup from a different address.
+;
+               test byte [LoadFlags],LOAD_HIGH
+               mov bx,real_mode_seg            ; Real mode segment
+               jnz in_proper_place             ; If high load, we're done
 ;
 ; Copy real_mode stuff up to 90000h
 ;
@@ -2114,11 +2126,6 @@ high_load_done:
                shl cx,7                        ; Sectors -> dwords
                xor eax,eax
                rep stosd                       ; Clear region
-;
-; Now, if we were supposed to load "low", copy the kernel down to 10000h
-;
-               test byte [LoadFlags],LOAD_HIGH
-               jnz in_proper_place             ; If high load, we're done
 
                mov ecx,[KernelSize]
                add ecx,3                       ; Round upwards
@@ -2126,7 +2133,14 @@ high_load_done:
                mov esi,100000h
                mov edi,10000h
                call bcopy
+
+               mov bx,9000h                    ; Real mode segment
+
+;
+; Now everything is where it needs to be...
+;
 in_proper_place:
+               mov es,bx                       ; Real mode segment
 ;
 ; If the default root device is set to FLOPPY (0000h), change to
 ; /dev/fd0 (0200h)
@@ -2139,21 +2153,25 @@ root_not_floppy:
 ; Copy the disk table to high memory, then re-initialize the floppy
 ; controller
 ;
+; This needs to be moved before the copy
+;
+%if 0
                push ds
+               push bx
                lds si,[fdctab]
                mov di,linux_fdctab
                mov cx,3                        ; 12 bytes
                push di
                rep movsd
                pop di
-               cli
                mov [fdctab1],di                ; Save new floppy tab pos
                mov [fdctab2],es
-               sti
                xor ax,ax
                xor dx,dx
                int 13h
+               pop bx
                pop ds
+%endif
 ;
 ; Linux wants the floppy motor shut off before starting the kernel,
 ; at least bootsect.S seems to imply so
@@ -2163,12 +2181,6 @@ kill_motor:
                xor al,al
                call slow_out
 ;
-; Now we're as close to be done as we can be and still use our normal
-; routines, print a CRLF to end the row of dots
-;
-               mov si,crlf_msg
-               call cwritestr
-;
 ; If we're debugging, wait for a keypress so we can read any debug messages
 ;
 %ifdef debug
@@ -2177,19 +2189,25 @@ kill_motor:
 %endif
 ;
 ; Set up segment registers and the Linux real-mode stack
+; Note: bx == the real mode segment
 ;
                cli
-               mov ax,9000h
-               mov ds,ax
-                mov es,ax
-               mov fs,ax
-               mov gs,ax
-               mov ss,ax
+               ; es is already == real mode segment
+               mov ds,bx
+               mov fs,bx
+               mov gs,bx
+               mov ss,bx
                mov sp,linux_stack
 ;
 ; We're done... now RUN THAT KERNEL!!!!
+; Setup segment == real mode segment + 020h; we need to jump to offset
+; zero in the real mode segment.
 ;
-               jmp setup_seg:setup_entry
+               add bx,020h
+               push bx
+               push word 0h
+               retf
+
 ;
 ; Load an older kernel.  Older kernels always have 4 setup sectors, can't have
 ; initrd, and are always loaded low.
@@ -3610,6 +3628,7 @@ err_bootsec       db 'Invalid or corrupt boot sector image.', 0Dh, 0Ah, 0
 err_a20                db 0Dh, 0Ah, 'A20 gate not responding!', 0Dh, 0Ah, 0
 err_bootfailed db 0Dh, 0Ah, 'Boot failed: please change disks and press '
                db 'a key to continue.', 0Dh, 0Ah, 0
+ready_msg      db ' ready.', 0Dh, 0Ah, 0
 loading_msg     db 'Loading ', 0
 dotdot_msg      db '.'
 dot_msg         db '.', 0