Add doc about reg

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Mathieu Maret 2017-01-28 23:40:54 +01:00
parent b2610491c7
commit 6e2f3fbd06
1 changed files with 22 additions and 0 deletions

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@ -14,6 +14,28 @@ Debug with
b *0x7c00
c
== ASM reg ==
=== In 16 bits ===
There is 4 main 16bits reg: AX, BX, CX, DX.
You can access the 8 MSB from AX with AH and the 8 LSB with AL.( BH,BL, CH, CL)
SI and DI are 16bits index register often used for pointer but can contains data.
SP is stack pointer, BP is base pointer
AX(AH, AL), BX(BH, BL), CX(CH, CL), DX(DH, DL), SI, DI, SP, BP
=== In 32bits ===
Main register are "Extended" to 32bits but 16bits of 8bits direct access is not possible anymore.
EAX, EBX, ECX, EDX, ESI, EDI, ESP, EBP
=== In 64bits ===
Prefixed by R
RAX, RBX, RCX, RDX, RSI, RDI, RSP, RBP
== Bios Memory ==
0x0 - 0x03FF ;IVT