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.section .data
newline:
.byte 10 # '\n'
tab:
.byte 9 # '\tab'
.section .text
# --------------------------------------------
# FUNCTION: print_tab
# PURPOSE : print a tab character ('\t')
# INPUTS :
# OUTPUTS :
# CLOBBERS: rax, rdi, rsi, rdx
# --------------------------------------------
.globl print_tab
.type print_tab, @function
print_tab:
movq $1, %rax # write
movq $1, %rdi # stdout
movq $tab, %rsi # load tab character
movq $1, %rdx # 1 byte
syscall
ret
# --------------------------------------------
# FUNCTION: print_newline
# PURPOSE : print a newline character ('\n')
# INPUTS :
# OUTPUTS :
# CLOBBERS: rax, rdi, rsi, rdx
# --------------------------------------------
.globl print_newline
.type print_newline, @function
print_newline:
movq $1, %rax # write
movq $1, %rdi # stdout
movq $newline, %rsi # load newline character
movq $1, %rdx # 1 byte
syscall
ret
# --------------------------------------------
# FUNCTION: print_buffer
# PURPOSE : take a buffer of coordinates and print each coordinate on a line
# INPUTS : rdi = pointer to buffer, rsi = number of coordinates
# OUTPUTS :
# CLOBBERS: rax, rdi,
# --------------------------------------------
.globl print_buffer
.type print_buffer, @function
print_buffer:
cmpq $0, %rsi
jle done # if n > 0 print_coordinate
movq %rdi, %rdx # keep pointer here, rdi will be used for print_num
loop:
movq (%rdx), %r15 # Pointer element
# print x and tab
movq (%r15), %rdi # Get first number from element
call print_num # Print it
push %rdx # save pointer
push %rsi # save n
call print_tab
pop %rsi # retrieve n
pop %rdx # retrieve pointer
# print y and newline
movq 8(%r15), %rdi # Get the second number
call print_num # Print it
push %rdx # save pointer
push %rsi # save n
call print_newline
pop %rsi # retrieve n
pop %rdx # retrieve pointer
# move to next coordinate and decq n
addq $8, %rdx
decq %rsi
cmpq $0, %rsi
jg loop
done:
ret
# Print RDI as an unsigned integer without any new line.
# Note: the function does not follow the ordinary calling convention,
# but restores all registers.
.type print_num, @function
.globl print_num
print_num:
push %rbp
movq %rsp, %rbp
# save
push %rax
push %rdi
push %rsi
push %rdx
push %rcx
push %r8
push %r9
movq %rdi, %rax # arg
movq $0, %r9 # digit count
.Lprint_num_convertLoop:
movq $0, %rdx
movq $10, %rcx
idivq %rcx
addq $48, %rdx # '0' is 48
push %rdx
addq $1, %r9
cmpq $0, %rax
jne .Lprint_num_convertLoop
.Lprint_num_printLoop:
movq $1, %rax # sys_write
movq $1, %rdi # stdout
movq %rsp, %rsi # buf
movq $1, %rdx # len
syscall
addq $8, %rsp
addq $-1, %r9
jne .Lprint_num_printLoop
# restore
pop %r9
pop %r8
pop %rcx
pop %rdx
pop %rsi
pop %rdi
pop %rax
movq %rbp, %rsp
pop %rbp
ret
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