The Microcode Update Loader
The Bare Bones Loader
The code fragment below represents a loader that adheres to the loader revision type 00000001h (see “Loader Revision” on page 635). The loader would be incorporated within the BIOS startup code (and the Microcode Image is also incorporated within the BIOS).
mov ecx,79h ;set ecx = address of Microcode Update MSR xor eax,eax ;clear eax xor ebx,ebx ;clear ebx mov ax,cs ;set ax =upper 4 digits of BIOS code segment base shl eax,4 ;add lower digit 0h to segment base address mov bx,offset Update ;set bx = offset of image from segment start add eax,ebx ;set eax = start of update in BIOS segment add eax,48d ;set eax = start of microcode image in segment xor edx,edx ;clear edx wrmsr ;Write to Update Trigger ...
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