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Created page with 'Category:Assembler== Registers == === General-Purpose Registers === The 64-bit versions of the 'original' x86 registers are named: * rax - register a extended * rbx - regis…'
[[Category:Assembler]]== Registers ==
=== General-Purpose Registers ===
The 64-bit versions of the 'original' x86 registers are named:
* rax - register a extended
* rbx - register b extended
* rcx - register c extended
* rdx - register d extended
* rbp - register base pointer (start of stack)
* rsp - register stack pointer (current location in stack, growing downwards)
* rsi - register source index (source for data copies)
* rdi - register destination index (destination for data copies)
The registers added for 64-bit mode are named:
* r8 - register 8
* r9 - register 9
* r10 - register 10
* r11 - register 11
* r12 - register 12
* r13 - register 13
* r14 - register 14
* r15 - register 15
These may be accessed as:
* 64-bit registers using the 'r' prefix: rax, r15
* 32-bit registers using the 'e' prefix (original registers: e_x) or 'd' suffix (added registers: r__d): eax, r15d
* 16-bit registers using no prefix (original registers: _x) or a 'd' suffix (added registers: r__d): ax, r15d
* 8-bit registers using 'h' suffix (original registers - bits 8-15: _h): ah, bh
* 8-bit registers using 'l' suffix (original registers - bits 0-7: _l) or 'b' suffix (added registers: r__b): al, bl, r15b
Usage during syscall/function call:
* First six arguments are in rdi, rsi, rdx, rcx, r8d, r9d; remaining arguments are on the stack
* For syscalls, the syscall number is in rax
* Return value is in rax
* The called routine is expected to save rsp,rbp, rbx, r12, r13, r14, and r15 but may trample any other registers
== Instructions ==
=== Starter Kit ===
These instructions are sufficient to complete the [[SPO600 Assembler Lab]]:
add %r10,%r11 // add r10 and r11, put result in r11
cmp %r10,%r11 // compare register r10 with register r11
cmp $99,%r11 // compare the number 99 with register r11
div $r10 // divide rax by the given register (r10), places quotient into rax and remainder into rdx (rdx must be zero before this instruction)
inc %r10 // increment r10
jmp ''label'' // jump to label
jeq ''label'' // jump to label if equal
jne ''label'' // jump to label if not equal
jl ''label'' // jump to label if less
jg ''label'' // jump to label if greater
mov %r10,%r11 // move data from r10 to r11
mov $99,%r10 // put the immediate value 99 into r10
mov %r10,(%r11) // move data from r10 to address pointed to by r11
mov (%r10),%r11 // move data from address pointed to by r10 to r10
mul $r10 // multiplies rax by r10, places result in rax and overflow in rdx
push %r10 // push r10 onto the stack
pop %r10 // pop r10 off the stack
== References ==
* For full information on the x86_64 registers and instruction set, see the Intel manuals: http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html
=== General-Purpose Registers ===
The 64-bit versions of the 'original' x86 registers are named:
* rax - register a extended
* rbx - register b extended
* rcx - register c extended
* rdx - register d extended
* rbp - register base pointer (start of stack)
* rsp - register stack pointer (current location in stack, growing downwards)
* rsi - register source index (source for data copies)
* rdi - register destination index (destination for data copies)
The registers added for 64-bit mode are named:
* r8 - register 8
* r9 - register 9
* r10 - register 10
* r11 - register 11
* r12 - register 12
* r13 - register 13
* r14 - register 14
* r15 - register 15
These may be accessed as:
* 64-bit registers using the 'r' prefix: rax, r15
* 32-bit registers using the 'e' prefix (original registers: e_x) or 'd' suffix (added registers: r__d): eax, r15d
* 16-bit registers using no prefix (original registers: _x) or a 'd' suffix (added registers: r__d): ax, r15d
* 8-bit registers using 'h' suffix (original registers - bits 8-15: _h): ah, bh
* 8-bit registers using 'l' suffix (original registers - bits 0-7: _l) or 'b' suffix (added registers: r__b): al, bl, r15b
Usage during syscall/function call:
* First six arguments are in rdi, rsi, rdx, rcx, r8d, r9d; remaining arguments are on the stack
* For syscalls, the syscall number is in rax
* Return value is in rax
* The called routine is expected to save rsp,rbp, rbx, r12, r13, r14, and r15 but may trample any other registers
== Instructions ==
=== Starter Kit ===
These instructions are sufficient to complete the [[SPO600 Assembler Lab]]:
add %r10,%r11 // add r10 and r11, put result in r11
cmp %r10,%r11 // compare register r10 with register r11
cmp $99,%r11 // compare the number 99 with register r11
div $r10 // divide rax by the given register (r10), places quotient into rax and remainder into rdx (rdx must be zero before this instruction)
inc %r10 // increment r10
jmp ''label'' // jump to label
jeq ''label'' // jump to label if equal
jne ''label'' // jump to label if not equal
jl ''label'' // jump to label if less
jg ''label'' // jump to label if greater
mov %r10,%r11 // move data from r10 to r11
mov $99,%r10 // put the immediate value 99 into r10
mov %r10,(%r11) // move data from r10 to address pointed to by r11
mov (%r10),%r11 // move data from address pointed to by r10 to r10
mul $r10 // multiplies rax by r10, places result in rax and overflow in rdx
push %r10 // push r10 onto the stack
pop %r10 // pop r10 off the stack
== References ==
* For full information on the x86_64 registers and instruction set, see the Intel manuals: http://www.intel.com/content/www/us/en/processors/architectures-software-developer-manuals.html