1 files changed, 46 insertions, 0 deletions
diff --git a/PGU/CHAP9/error.s b/PGU/CHAP9/error.s
new file mode 100644
index 0000000..6e933ed
--- /dev/null
+++ b/PGU/CHAP9/error.s
@@ -0,0 +1,46 @@
+# Error function
+#
+# Print error messages and exit program.
+
+.include "linux.s"
+.equ ST_ERROR_CODE, 16
+.equ ST_ERROR_MSG, 24
+
+.globl error_exit
+.type error_exit, @function
+
+error_exit:
+	pushq %rbp
+	movq %rsp, %rbp
+
+	# Write error Code
+	movq ST_ERROR_CODE(%rbp), %rcx
+	pushq %rcx
+	call count_chars
+	popq %rcx
+
+	movq %rax, %rdx
+	movq %rcx, %rsi
+	movq $STDERR, %rdi
+	movq $SYS_WRITE, %rax
+	syscall
+
+	# Write error message
+	movq ST_ERROR_MSG(%rbp), %rcx
+	pushq %rcx
+	call count_chars
+	popq %rcx
+
+	movq %rax, %rdx		# How many bytes to write
+	movq %rcx, %rsi		# Buffer to write from
+	movq $STDERR, %rdi	# FD to write to
+	movq $SYS_WRITE, %rax	# self explanatory
+	syscall
+
+	pushq $STDERR
+	call write_newline
+
+	# Exit program
+	movq $SYS_EXIT, %rax
+	movq $1, %rdi
+	syscall