- LOGIC PRO 8 BIT TUTORIAL MANUALS
- LOGIC PRO 8 BIT TUTORIAL 64 BITS
- LOGIC PRO 8 BIT TUTORIAL CODE
Writing standalone programs with just system calls is cool, but rare. It simply defines an abbreviation for the assembler itself to use. equ is actually not a real instruction.We also have jne (jump if not equal), jl (jump if less), jnl (jump if not less), jg (jump if greater), jng (jump if not greater), jle (jump if less or equal), jnle (jump if not less or equal), jge (jump if greater or equal), jnge (jump if not greater or equal), and many more.
je jumps to a label if the previous comparison was equal. $ nasm -fmacho64 triangle.asm & ld triangle.o &. Syscall invoke operating system to do the write Mov rsi, output address of string to output Mov rax, 0x02000004 system call for write Mov r9, 0 reset count of stars written on this lineĬmp r8, maxlines wait, did we already finish the last line? Inc rdx and move pointer to where next char goes Jne line not yet, keep writing on this line Inc rdx advance pointer to next cell to writeĬmp r9, r8 did we reach the number of stars for this line? Mov r9, 0 number of stars written on line so far Mov rdx, output rdx holds address of next byte to write nasm -fmacho64 triangle.asm & gcc hola.o &. This is an OSX console program that writes a little triangle of asterisks to standard bss (you'll get an error if you try to use them in To reserve space (without initializing), you can use the following pseudo instructions. There are other forms check the NASM docs. To place data in memory:ĭb 0x55,0x56,0x57 three bytes in successionĭb 'hello',13,10,'$' so are string constantsĭq 0x123456789abcdef0 eight byte constantĭt 1.234567e20 extended-precision float These examples come from Chapter 3 of the docs. Most of the basic instructions have onlyĪdd reg, reg add reg, mem add reg, imm add mem, reg add mem, imm Defining Data and Reserving Space In fact, we’ll not see any such instruction in this tutorial. Instructions with two memory operands are extremely rare Here are some examples from the official docs.Ġ200 still decimal - the leading 0 does not make it octalĠc8h hex - h suffix, but leading 0 is required because c8h looks like a varĠhc8 hex - for some reason NASM likes 0hĠb1100_1000 binary - 0b prefix, and by the way, underscores are allowed uses the address of the variable 'counter' as the displacement The base the register with the scale is called the index. The number is called the displacement the plain register is called R3 are named:Īnd finally, there are 16 XMM registers, each 128 bits wide, named: R0B R1B R2B R3B R4B R5B R6B R7B R8B R9B R10B R11B R12B R13B R14B R15Bįor historical reasons, bits 15 through 8 of R0. You can treat the lowest 8-bits of each register as a register itself but using these names: You can treat the lowest 16-bits of each register as a register itself but using these names: (Note that 8 of the registers have alternate names.) You can treat the lowestģ2-bits of each register as a register itself but using these names: LOGIC PRO 8 BIT TUTORIAL 64 BITS
The 16 integer registers are 64 bits wide and are called: You should already know what the registers are, but here is a quick In this tutorial we only care about the integer registers and the xmm The Three Kinds of Operands Register Operands That declares bytes that will be in memory when the program runs Syscall Invoke an operating system routine Mov x, y x ← y and x, y x ← x and y or x, y x ← x or y xor x, y x ← x xor y add x, y x ← x + y sub x, y x ← x – y inc x x ← x + 1
LOGIC PRO 8 BIT TUTORIAL MANUALS
The Intel Processor Manuals Your First Few Instructions. NASM is an awesome assembler, but assembly language is complex. 
text and your constant data in a section called.
LOGIC PRO 8 BIT TUTORIAL CODE
Generally, you put code in a section called. Most lines have an instruction followed by zero or more operands. Most programs consist of directives followed by one or more sections. Exercise: Identify the differences between the two programs.
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