UefiCpuPkg: Add a 16-bit protected mode code segment descriptor

[mirror_edk2.git] / UefiCpuPkg / ResetVector / Vtf0 / Ia16 / Real16ToFlat32.asm

diff --git a/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm b/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm
index ce4ebfffb688e06e67488246e585cf4c1e9015af..0e79a3984b168fa435e4186e046eb5451a58dac2 100644 (file)
--- a/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm
+++ b/UefiCpuPkg/ResetVector/Vtf0/Ia16/Real16ToFlat32.asm
@@ -129,5 +129,14 @@ LINEAR_CODE64_SEL   equ $-GDT_BASE
     DB      0            ; base 31:24\r
 %endif\r
 \r
+; linear code segment descriptor\r
+LINEAR_CODE16_SEL     equ $-GDT_BASE\r
+    DW      0xffff       ; limit 15:0\r
+    DW      0            ; base 15:0\r
+    DB      0            ; base 23:16\r
+    DB      PRESENT_FLAG(1)|DPL(0)|SYSTEM_FLAG(1)|DESC_TYPE(CODE32_TYPE)\r
+    DB      GRANULARITY_FLAG(1)|DEFAULT_SIZE32(0)|CODE64_FLAG(0)|UPPER_LIMIT(0xf)\r
+    DB      0            ; base 31:24\r
+\r
 GDT_END:\r
 \r