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https://github.com/williamkosasih19/jit-nasm
Just In Time NASM. Assemble and run instructions in memory, immediately
https://github.com/williamkosasih19/jit-nasm
asmjit assembler assembler-x86 assembly c compiler jit jit-assembler x86 x86-64
Last synced: 12 days ago
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Just In Time NASM. Assemble and run instructions in memory, immediately
- Host: GitHub
- URL: https://github.com/williamkosasih19/jit-nasm
- Owner: williamkosasih19
- License: other
- Created: 2022-09-04T11:57:40.000Z (over 2 years ago)
- Default Branch: master
- Last Pushed: 2022-10-19T14:30:47.000Z (over 2 years ago)
- Last Synced: 2024-11-21T17:44:26.029Z (2 months ago)
- Topics: asmjit, assembler, assembler-x86, assembly, c, compiler, jit, jit-assembler, x86, x86-64
- Language: Assembly
- Homepage:
- Size: 1.4 MB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGES
- License: LICENSE
- Authors: AUTHORS
Awesome Lists containing this project
README
# Just In Time NASM
Assemble your assemble listings and call it instantaneously within your program.
## Build
To build jit-nasm, simply run the command
`$ ./autogen.sh`
`$ ./configure`
`$ make`
inside the code directory.
## Install Library
To install the jit-nasm library, do the following after building
`$ sudo make install PREFIX=/usr/local`
to install libjitnasm in /usr/local/lib
## Usage
To link your code with jit-nasm, use -ljitnasm
`$ gcc your_code.c -ljitnasm`
### Instantiate Library
To initialize library, first do the following
```
#include
jit_nasm_t jnasm = jit_nasm_create_instance(NULL, 0); // interface: jit_nasm_create_instance(pointer to buffer, buffer size). These two parameters are used for external buffer. Default value is NULL, where jit-nasm will allocate the buffer used to assemble instructions internally.
```
### Assemble Instructions
To assemble instructions, do the following after initialization
```
jit_nasm_t jnasm = jit_nasm_create_instance(NULL, 0);
jit_nasm_assemble(jnasm, "mov rdx, 0x14fff\n"
"mov rax, 4\n"
"cmp rax, 3\n"
"je label_1\n"
"add rax, 34\n"
"label_1: xor rax, rdx\n"
"imul rax, rax\n"
"idiv rdx\n"
"ret\n", 0, NULL); // interface: jit_nasm(jit-nasm struct pointer, code to assemble, argc, argv). argc and argv are used by nasm for more advanced control over the program. Defaults to 0 and NULL.
```
### Getting Pointer to Assembled Code
After assembling your code, you can do the following to execute it.
```
jit_nasm_t jnasm = jit_nasm_create_instance(NULL, 0);
jit_nasm_assemble(jnasm, "mov rdx, 0x14fff\n"
"mov rax, 4\n"
"cmp rax, 3\n"
"je label_1\n"
"add rax, 34\n"
"label_1: xor rax, rdx\n"
"imul rax, rax\n"
"idiv rdx\n"
"ret\n", 0, NULL);
void (*func)() = jit_nasm_get_code(jnasm); // Cast value to a void function pointer
func(); // Call the code.
```
## Hello World Example
Demo located in the demo/ folder
```
#include
#include
#include
int main() {
const char* msg = "Hello World!\n";
char* code =
"mov rdx, rsi\n"
"mov rsi, rdi\n"
"mov rax, 1\n"
"mov rdi, 1\n"
"syscall\n"
"xor rax, rax\n"
"ret\n";
jit_nasm_t jnasm = jit_nasm_create_instance(NULL, 0);
jit_nasm_assemble(jnasm, code, 0, NULL);
void (*hello_world)(char*, int) = jit_nasm_get_code(jnasm);
hello_world(msg, 13);
jit_nasm_destroy_instance(jnasm);
}
```
outputs
`Hello World!`
Original NASM Readme Below
---
NASM, the Netwide Assembler
===========================
[](https://travis-ci.org/netwide-assembler/nasm)
Many many developers all over the net respect NASM for what it is:
a widespread (thus netwide), portable (thus netwide!), very flexible
and mature assembler tool with support for many output formats (thus netwide!!).
Now we have good news for you: NASM is licensed under the "simplified"
[(2-clause) BSD license](https://opensource.org/licenses/BSD-2-Clause).
This means its development is open to even wider society of programmers
wishing to improve their lovely assembler.
Visit our [nasm.us](https://www.nasm.us/) website for more details.
With best regards, the NASM crew.