 SU.HARDW.PC.MOTHERBOARD (2:5020/299)  SU.HARDW.PC.MOTHERBOARD 
 From : Alexey B Shamarokov                 2:5020/487.8    Fri 16 Jun 95 00:59 
 Subj : UMC498                                                                  


UMC 498 (PC Chips 18) registers

Index port 28h
Data  port 2Ah
Status: protected
Ŀ
Index    Function                     Description                      
Ĵ
031h   Set up C0000  00000000b                                         
       shadow memory  1 shadow enabled at CC000-CFFFF         
                      ? (cached CC000-CFFFF)                  
                      1 shadow enabled at C8000-CBFFF         
                      ? (cached C8000-CBFFF)                  
                      1 shadow enabled at C4000-C7FFF         
                      ? (cached C4000-C7FFF)                  
                      1 shadow enabled at C0000-C3FFF         
                      ? (cached C0000-C3FFF)                  
Ĵ
032h   Set up D0000  00000000b                                         
       shadow memory  1 shadow enabled at DC000-DFFFF         
                      ? (cached DC000-DFFFF)                  
                      1 shadow enabled at D8000-DBFFF         
                      ? (cached D8000-DBFFF)                  
                      1 shadow enabled at D4000-D7FFF         
                      ? (cached D4000-D7FFF)                  
                      1 shadow enabled at D0000-D3FFF         
                      ? (cached D0000-D3FFF)                  
Ĵ
033h   Write enable  00000000b                                         
                      0 write enable to DC000-DFFFF           
                      0 write enable to D8000-DBFFF           
                      0 write enable to D4000-D7FFF           
                      0 write enable to D0000-D3FFF           
                      0 write enable to CC000-CFFFF           
                      0 write enable to C8000-CBFFF           
                      0 write enable to C4000-C7FFF           
                      0 write enable to C0000-C3FFF           
Ĵ
035h   E0000         00000000b                                         
                      ?                                       
                      ?                                       
                      0 write enable to E8000-EFFFF           
                      0 write enable to E0000-E7FFF           
                      ?                                       
                      ?                                       
                      1 shadow enable at E0000-EFFFF          
                      ? (cached E0000-EFFFF)                  
Ĵ
036h   F0000         00000000b                                         
                      ?                                       
                      ?                                       
                      ?                                       
                      ?                                       
                      ?                                       
                      0 write enable to F0000-FFFFF           
                      1 shadow enable at F0000-FFFFF          
                      ? (cached F0000-FFFFF)                  

  ᮢᥬ ୠ: 室 ஢  ⮢  稥
-      ᥣ,   UMC 491.
;
clear_protection proc
                 mov    al,0A0h
                 out    28h,al
                 jmp    $+2
                 jmp    $+2
                 mov    al,05h
                 out    28h,al
                 jmp    $+2
                 jmp    $+2
                 ret
clear_protection endp
;
;
set_protection   proc
                 mov    al,0A5h
                 out    28h,al
                 jmp    $+2
                 jmp    $+2
                 ret
set_protection   endp

---
 * Origin: Wind Trap mail station (2:5020/487.8)

