19 files changed, 163 insertions, 0 deletions

diff --git a/x86_64/Makefile b/x86_64/Makefile
new file mode 100644
index 0000000..4096a79
--- /dev/null
+++ b/x86_64/Makefile
@@ -0,0 +1,13 @@
+
+OBJS = exit.o arithmetic.o reg_size.o jmp_havoc.o exponent.o mul_by_add.o
+
+all: $(OBJS)
+	ld -o exit exit.o
+	ld -o arithmetic arithmetic.o
+	ld -o reg_size reg_size.o
+	ld -o jmp_havoc jmp_havoc.o
+	ld -o exponent exponent.o
+	ld -o mul_by_add mul_by_add.o
+
+clean:
+	rm $(OBJS)
diff --git a/x86_64/arithmetic b/x86_64/arithmetic
new file mode 100755
index 0000000..b8fd40a
--- /dev/null
+++ b/x86_64/arithmetic
diff --git a/x86_64/arithmetic.o b/x86_64/arithmetic.o
new file mode 100644
index 0000000..9d258f5
--- /dev/null
+++ b/x86_64/arithmetic.o
diff --git a/x86_64/arithmetic.s b/x86_64/arithmetic.s
new file mode 100644
index 0000000..34216f1
--- /dev/null
+++ b/x86_64/arithmetic.s
@@ -0,0 +1,22 @@
+# Simple program exercising CPU's arithmetic instructions
+
+.globl _start
+
+.section .text
+
+_start:
+	movq $3, %rdi
+	movq %rdi, %rax
+	mulq %rdi
+	movq $2, %rdi
+	addq %rdi, %rax
+	movq $4, %rdi
+	mulq %rdi
+
+	movq $10, %rax
+	movq $3, %rdi
+	divq %rdi	 # Remainder goes to %rdx
+	movq %rax, %rdi
+
+	mov $60, %rax
+	syscall
diff --git a/x86_64/exit b/x86_64/exit
new file mode 100755
index 0000000..c9bb3ab
--- /dev/null
+++ b/x86_64/exit
diff --git a/x86_64/exit.o b/x86_64/exit.o
new file mode 100644
index 0000000..44033df
--- /dev/null
+++ b/x86_64/exit.o
diff --git a/x86_64/exit.s b/x86_64/exit.s
new file mode 100644
index 0000000..d9c594f
--- /dev/null
+++ b/x86_64/exit.s
@@ -0,0 +1,10 @@
+# Simple program that just exits with a simple status code
+
+.globl _start
+
+.section .text
+
+_start:
+	movq $60, %rax	# sys_exit
+	movq $66, %rdi
+	syscall
diff --git a/x86_64/exponent b/x86_64/exponent
new file mode 100755
index 0000000..ce3f124
--- /dev/null
+++ b/x86_64/exponent
diff --git a/x86_64/exponent.o b/x86_64/exponent.o
new file mode 100644
index 0000000..516d6c5
--- /dev/null
+++ b/x86_64/exponent.o
diff --git a/x86_64/exponent.s b/x86_64/exponent.s
new file mode 100644
index 0000000..e469d26
--- /dev/null
+++ b/x86_64/exponent.s
@@ -0,0 +1,37 @@
+# Compute a^b, where %rbx=a and %rcx=b
+#
+# Result is added to the accumulator (%rax)
+
+
+.globl _start
+
+.section .text
+
+_start:
+	movq	$2, %rbx # Base
+	movq	$5, %rcx # Exponent
+
+	movq	$1, %rax # Initialize accumulator, take advantage of the fact
+			 # that anything to the power of 0 is 1.
+
+	# We just need to run this once, as decq will set ZF if %rcx reaches
+	# zero, and the jmp instruction does nothing with the ZF
+	cmpq	$0, %rcx
+	je	complete
+
+mainloop:
+
+	# Multiply %rbx by %rax, and stores the result in %rax
+	# Hence %rax is the accumulator register
+	mulq	%rbx
+
+	# loopq instruction is very nice, in a single instruction it does:
+	#	- decrement %rcx - The counter register -
+	#	- compare %rcx to zero
+	#	- Jump to the location specified if after decrementing %rcx is not 0
+	loopq	mainloop
+
+complete:
+	movq	%rax, %rdi
+	movq	$60, %rax
+	syscall
diff --git a/x86_64/jmp_havoc b/x86_64/jmp_havoc
new file mode 100755
index 0000000..6c22ca7
--- /dev/null
+++ b/x86_64/jmp_havoc
diff --git a/x86_64/jmp_havoc.o b/x86_64/jmp_havoc.o
new file mode 100644
index 0000000..1e65228
--- /dev/null
+++ b/x86_64/jmp_havoc.o
diff --git a/x86_64/jmp_havoc.s b/x86_64/jmp_havoc.s
new file mode 100644
index 0000000..6dd734d
--- /dev/null
+++ b/x86_64/jmp_havoc.s
@@ -0,0 +1,39 @@
+# Play around with jumps
+
+.section .text
+.globl _start
+
+_start:
+	movq	$25, %rax
+	jmp	thelabel
+
+somewhere:
+	movq	%rax, %rdi
+	jmp	anotherlabel
+
+label1:
+	addq	%rbx, %rax
+	movq	$5, %rbx
+	jmp	here
+
+labellabel:
+	syscall
+
+anotherlabel:
+	movq	$60, %rax
+	jmp	labellabel
+
+thelabel:
+	movq	%rax, %rbx
+	jmp	there
+
+here:
+	divq	%rbx
+	jmp somewhere
+
+there:
+	addq	$5, %rbx
+	jmp	label1
+
+anywhere:
+	jmp	thelabel
diff --git a/x86_64/mul_by_add b/x86_64/mul_by_add
new file mode 100755
index 0000000..1850861
--- /dev/null
+++ b/x86_64/mul_by_add
diff --git a/x86_64/mul_by_add.o b/x86_64/mul_by_add.o
new file mode 100644
index 0000000..7d7e01a
--- /dev/null
+++ b/x86_64/mul_by_add.o
diff --git a/x86_64/mul_by_add.s b/x86_64/mul_by_add.s
new file mode 100644
index 0000000..3e8c360
--- /dev/null
+++ b/x86_64/mul_by_add.s
@@ -0,0 +1,25 @@
+# Do a multiplication without using mulq, resulting in a * b
+.section .text
+.globl _start
+
+.set OP, 1	# Set here the numbers to
+.set OP2, 1	# be multiplied
+
+_start:
+	movq	$OP2, %rcx
+	movq	$0, %rax
+
+	# We can't rely on loopq to drop exit the loop in case OP2
+	# is 0, because the first iteraction will cause %rcx to be -1
+	cmpq	$OP2, %rax
+	je	exit
+
+
+addloop:
+	addq	$OP, %rax
+	loopq addloop
+
+exit:
+	movq	%rax, %rdi
+	movq	$60, %rax
+	syscall
diff --git a/x86_64/reg_size b/x86_64/reg_size
new file mode 100755
index 0000000..eec38b7
--- /dev/null
+++ b/x86_64/reg_size
diff --git a/x86_64/reg_size.o b/x86_64/reg_size.o
new file mode 100644
index 0000000..1622ccf
--- /dev/null
+++ b/x86_64/reg_size.o
diff --git a/x86_64/reg_size.s b/x86_64/reg_size.s
new file mode 100644
index 0000000..e374922
--- /dev/null
+++ b/x86_64/reg_size.s
@@ -0,0 +1,17 @@
+# Program to play around with different register sizes
+
+.set exit_num, 60
+
+.section .text
+.globl _start
+
+_start:
+	movw	$0b0000101000000101, %bx  #10d and 5d into high and low registers
+	addb	%bh, %bl
+	movb	$0, %bh
+
+	# %bh now contains 10+5, use it as an argument to exit()
+
+	movq	%rbx, %rdi
+	movq	$exit_num, %rax
+	syscall