Yet more fixes to the new A20 code.

diff --git a/ldlinux.asm b/ldlinux.asm
index 74fb5f3..bfb483d 100644 (file)
--- a/ldlinux.asm
+++ b/ldlinux.asm
@@ -2552,6 +2552,7 @@ _io_delay:        out IO_DELAY_PORT,al
                ret
 
 enable_a20:
+               pushad
                mov byte [ss:A20Tries],255 ; Times to try to make this work
 
 try_enable_a20:
@@ -2563,7 +2564,8 @@ try_enable_a20:
 ;
 ; If the A20 type is known, jump straight to type
 ;
-               movzx bp,byte [ss:A20Type]
+               mov bp,[ss:A20Type]
+               add bp,bp                       ; Convert to word offset
                jmp word [bp+A20List]           ; Implicit ss: because of bp
 
 ;
@@ -2581,7 +2583,9 @@ a20_none:
 a20_bios:
                mov byte [ss:A20Type], A20_BIOS
                mov ax,2401h
+               pushf                           ; Some BIOSes muck with IF
                int 15h
+               popf
 
                call a20_test
                jnz a20_done
@@ -2652,7 +2656,8 @@ a20_fast:
 ; A20 unmasked, proceed...
 ;
 a20_done_pop:  pop cx
-a20_done:      ret
+a20_done:      popad
+               ret
 
 ;
 ; This routine tests if A20 is enabled (ZF = 0).  This routine
@@ -2677,17 +2682,21 @@ a20_test:
                ret
 
 disable_a20:
+               pushad
 ;
 ; Flush the caches
 ;
 ;              call try_wbinvd
 
-               movzx bp,byte [ss:A20Type]
+               mov bp,[ss:A20Type]
+               add bp,bp                       ; Convert to word offset
                jmp word [bp+A20DList]          ; Implicit ss: because of bp
 
 a20d_bios:
                mov ax,2400h
+               pushf                           ; Some BIOSes muck with IF
                int 15h
+               popf
                jmp short a20d_snooze
 
 ;
@@ -2720,6 +2729,7 @@ a20d_snooze:
 .disabled:     pop cx
 a20d_dunno:
 a20d_none:
+               popad
                ret
 
 ;
@@ -3879,7 +3889,7 @@ AllowImplicit   dw 1                    ; Allow implicit kernels
 SerialPort     dw 0                    ; Serial port base (or 0 for no serial port)
 A20List                dw a20_dunno, a20_none, a20_bios, a20_kbc, a20_fast
 A20DList       dw a20d_dunno, a20d_none, a20d_bios, a20d_kbc, a20d_fast
-A20Type                db A20_DUNNO            ; A20 type unknown
+A20Type                dw A20_DUNNO            ; A20 type unknown
 ;
 ; Stuff for the command line; we do some trickery here with equ to avoid
 ; tons of zeros appended to our file and wasting space

diff --git a/pxelinux.asm b/pxelinux.asm
index 8906758..9614378 100644 (file)
--- a/pxelinux.asm
+++ b/pxelinux.asm
@@ -2133,6 +2133,7 @@ _io_delay:        out IO_DELAY_PORT,al
                ret
 
 enable_a20:
+               pushad
                mov byte [ss:A20Tries],255 ; Times to try to make this work
 
 try_enable_a20:
@@ -2144,7 +2145,8 @@ try_enable_a20:
 ;
 ; If the A20 type is known, jump straight to type
 ;
-               movzx bp,byte [ss:A20Type]
+               mov bp,[ss:A20Type]
+               add bp,bp                       ; Convert to word offset
                jmp word [bp+A20List]           ; Implicit ss: because of bp
 
 ;
@@ -2162,7 +2164,9 @@ a20_none:
 a20_bios:
                mov byte [ss:A20Type], A20_BIOS
                mov ax,2401h
+               pushf                           ; Some BIOSes muck with IF
                int 15h
+               popf
 
                call a20_test
                jnz a20_done
@@ -2233,7 +2237,8 @@ a20_fast:
 ; A20 unmasked, proceed...
 ;
 a20_done_pop:  pop cx
-a20_done:      ret
+a20_done:      popad
+               ret
 
 ;
 ; This routine tests if A20 is enabled (ZF = 0).  This routine
@@ -2258,17 +2263,21 @@ a20_test:
                ret
 
 disable_a20:
+               pushad
 ;
 ; Flush the caches
 ;
 ;              call try_wbinvd
 
-               movzx bp,byte [ss:A20Type]
+               mov bp,[ss:A20Type]
+               add bp,bp                       ; Convert to word offset
                jmp word [bp+A20DList]          ; Implicit ss: because of bp
 
 a20d_bios:
                mov ax,2400h
+               pushf                           ; Some BIOSes muck with IF
                int 15h
+               popf
                jmp short a20d_snooze
 
 ;
@@ -2301,6 +2310,7 @@ a20d_snooze:
 .disabled:     pop cx
 a20d_dunno:
 a20d_none:
+               popad
                ret
 
 ;
@@ -3979,7 +3989,7 @@ SerialPort        dw 0                    ; Serial port base (or 0 for no serial port)
 MySocket       dw 32768                ; Local UDP socket counter
 A20List                dw a20_dunno, a20_none, a20_bios, a20_kbc, a20_fast
 A20DList       dw a20d_dunno, a20d_none, a20d_bios, a20d_kbc, a20d_fast
-A20Type                db A20_DUNNO            ; A20 type unknown
+A20Type                dw A20_DUNNO            ; A20 type unknown
 
 ;
 ; TFTP commands