annatar/x86-cheatsheet
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Fix j*cxz encodings.

Browse Source
This commit is contained in:
Milan Špinka
2025-07-23 22:53:28 +02:00
parent ecdd043192
commit a9ad6026c6
1 changed files with 40 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
cheatsheet.md
View File

@ -643,13 +643,12 @@ todo: far jumps
**Short jump encodings available in both 32-bit and 64-bit modes:**
| Opcode | Operands | Assembly | Description | Test |
| ------- | -------- | ---------------- | ----------------------------------- | ---------------- |
| ------- | -------- | --------------- | ----------------------------------- | ---------------- |
| `77 ??` | rel8 | `ja $+2+rel8` | Jump short if above. | CF=0 and ZF=0 |
| `73 ??` | rel8 | `jae $+2+rel8` | Jump short if above or equal. | CF=0 |
| `72 ??` | rel8 | `jb $+2+rel8` | Jump short if below (CF=1). | CF=1 |
| `76 ??` | rel8 | `jbe $+2+rel8` | Jump short if below or equal. | CF=1 or ZF=1 |
| `72 ??` | rel8 | `jc $+2+rel8` | Jump short if carry. | CF=1 |
| `E3 ??` | rel8 | `jecxz $+2+rel8` | Jump short if ECX register is 0. | ECX=0 |
| `74 ??` | rel8 | `je $+2+rel8` | Jump short if equal. | ZF=1 |
| `7F ??` | rel8 | `jg $+2+rel8` | Jump short if greater. | ZF=0 and SF=OF |
| `7D ??` | rel8 | `jge $+2+rel8` | Jump short if greater or equal. | SF=OF |
@ -679,14 +678,16 @@ todo: far jumps
**Short jump encodings only available in 32-bit mode:**
| Opcode | Operands | Assembly | Description | Test |
| ------- | -------- | --------------- | ------------------------------- | ---- |
| `E3 cb` | rel8 | `jcxz $+2+rel8` | Jump short if CX register is 0. | CX=0 |
| ---------- | -------- | ---------------- | -------------------------------- | ----- |
| `67 E3 ??` | rel8 | `jcxz $+3+rel8` | Jump short if CX register is 0. | CX=0 |
| `E3 ??` | rel8 | `jecxz $+2+rel8` | Jump short if ECX register is 0. | ECX=0 |
**Short jump encodings only available in 64-bit mode:**
| Opcode | Operands | Assembly | Description | Test |
| ------- | -------- | ---------------- | -------------------------------- | ----- |
| `E3 cb` | rel8 | `jrcxz $+2+rel8` | Jump short if RCX register is 0. | RCX=0 |
| ---------- | -------- | ---------------- | -------------------------------- | ----- |
| `67 E3 ??` | rel8 | `jecxz $+3+rel8` | Jump short if ECX register is 0. | ECX=0 |
| `E3 ??` | rel8 | `jrcxz $+2+rel8` | Jump short if RCX register is 0. | RCX=0 |
**Near relative jump encodings available in both 32-bit and 64-bit modes:**