NB Assembler

Assembler and Decompiler for NVIDIA (Maxwell Pascal Volta Turing Ampere) GPUs.

Requirements:

• Python >= 3.8
• CUDA >= 6.5 (Only requires nvdisasm for disassembly or testing)

Supported NVIDIA GPUs:

Maxwell (SM50, SM52, SM53)

Pascal (SM60, SM61, SM62)

Volta (SM70, SM72)

Turing (SM75)

Ampere (SM80, SM86)

Install

python setup.py install

Use

# help
nbasm -h

# usage: nbasm [-h] [-V] {list,das,as,pre,pdas,test,det} ...

# Assembler and Decompiler for NVIDIA (Maxwell Pascal Volta Turing Ampere) GPUs.

# optional arguments:
#   -h, --help            show this help message and exit
#   -V, --version         Print version information on this tool.

# subcommands:
#   {list,das,as,pre,pdas,test,det}
#     list                list cubin info
#     das                 disassemble cubin
#     as                  assemble asm
#     dcc                 decompile asm to ptx
#     test                test assembler by disassemble and then assemble
#     det                 detect machine code bits

# examples
nbasm list ethash.cubin 
nbasm das -k Search -o ethash_search.s ethash.cubin
nbasm as -D DEBUG=True -o ethash.cubin ethash_search.s
nbasm dcc -o ethash.ptx ethash.s

ASM Grammar

# 单行注释
# 反汇编出来的其它用不到的元信息将写入文件头的注释。汇编时忽略。
/* 多行注释 */
.compute_75  # virtual_arch
.sm_75  # arch
.global: NAME  # 全局变量
	.align 8
	.zero 368
	.byte 0xff, 0xff, 0xff, 0x7f
	.short 0x0412
	.word 0x00000020
	.quad 0x366803807ff7021f
.constants: NAME  # 用户自定义常量
    .align 4
    .zero 4
.constants2: NAME  # 编译器生成的常量，一般由于代码中有指令编码存不下的立即数
    .align 4
    .zero 4

# 引用其它文件

# include汇编文件，直接在这个位置替换位汇编文件的内容
.include "source.s"

# include Python源代码，将会先执行这个Python脚本，执行后，使用Python上向文中out_变量的内容在这个位置替换
.include "source.py"

.constants: {python expression}  # {}中间的内容（单行）为Python表达式，计算表达式结果并在这个位置替换
    ...

# {}中间内容（多行）则视为Python代码，执行Python代码后使用Python上向文中out_变量的内容在这个位置替换
{
# 例如，条件include
if define1:
    out += '.include "source1.s"\n'
else:
    out += '.include "source2.s"\n'
out = '''
...
'''
}

.kernel: NAME  # kernel定义与代码
	# 普通寄存器别名映射，支持单个映射和批量映射（类似数组的用法）
	.reg NAME, Rxx
	# Uniform寄存器别名映射
	.reg NAME, URxx-xx
	# Pred寄存器别名映射
	.reg NAME, Pxx
	# Uniform Pred寄存器别名映射
	.reg NAME, UPxx
	# Kernel参数
	.param ordinal, NAME, SIZE_IN_BYTES
	# shared
	.shared SIZE_IN_BYTES

.L_label: #标签
    # 指令：/*地址*/  控制码   pred 指令.标志...  操作数, ...;    /* 指令编码 */ # reuse编码
	/*1dd0*/  -:--:-:-:Y:8  @!P6 IMAD.SHL.U32 R2, R2, 0x2, RZ;    /* 0x000fd000078e00ff000000020202e824 */ # ----
	# 控制码： schedule_flag:Wait_barrier_mask:read_barrier_index:write_barrier_index:yield:stall
	#	schedule_flag: 调度标志，仅供nbasm的调度器使用。默认自动调度。设置为'K'表示已经手工调好了这条指令的控制码，调度器忽略这条指令。
	#	Wait_barrier_mask: 等待read_barrier、write_barrier的位图
	#	read_barrier_index: 不定周期指令设置读后写依赖
	#	write_barrier_index: 不定周期指令设置写后读依赖
	#	yield: 让出,表示当前warp可以被换出。一般用于stall超过4个周期情况
	#	stall: 本条指令调度后，下一条指令延迟开始的周期数

Related projects

AsFermi, an SASS assembler for NVIDIA Fermi GPUs. By Hou Yunqing.

KeplerAs, an SASS assembler for NVIDIA Kepler. By Xiuxia Zhang.

MaxAs, an SASS assembler for NVIDIA Maxwell and Pascal. By Scott Gray.

TuringAs, an SASS assembler for NVIDIA Volta and Turing. By Da Yan.

This project is released under the MIT License.

-- Alvin Zhu