NASM Assembler codes for Win
Let's start with registers and their assignments:
| Name 64 bit | Assignments | Preserved across function calls |
|---|---|---|
| RAX | return register | Volatile |
| RBX | ? | |
| RDI | Nonvolatile | |
| RSI | Nonvolatile | |
| RCX | 1rd argument | Volatile |
| RDX | 2th argument | Volatile |
| RBP | ? | |
| RSP | Stack pointer | Nonvolatile |
| R8 | 3th argument | Volatile |
| R9 | 4th arguemnt | Volatile |
| R10 | Volatile | |
| R11 | Volatile | |
| ... | ... | ... |
| R15 | ? |
| Name 128 bit | Assignments | Preserved across function calls | 32 bit | 16 bit | 8 bit |
|---|---|---|---|---|---|
| XMMO | floating point, 1st argument, return register | no | |||
| XMM1 | floating point, 2sd argument | no | . | . | . |
| XMM2 | floating point, 3rd argument | no | . | . | . |
| XMM3 | floating point, 4th argument | no | . | . | . |
| ... | ... | ... | . | . | . |
| XMM15 | . | no | . | . | . |
Example:
func(int a, double b, int c, float d, int e, float f);
a in RCX, b in XMM1, c in R8, d in XMM3, f then e pushed on stack