我试图从用户那里读取输入并进行打印。 首先，我向用户打印请求，用户输入一个值，然后我想打印它。
.data
params_sys5: .space 8
params_sys3: .space 8
prompt_msg_LBound: .asciiz "Enter lower bound for x,y\n"
prompt_msg_LBound_val: .asciiz "Lower bound for x,y = %d\n"
xyL: .word64 0
prompt_msg_UBound: .asciiz "Enter upper bound for x,y\n"
prompt_msg_UBound_val: .asciiz "Upper bound for x,y = %d\n"
xyU: .word64 0
prompt_msg_UBoundZ: .asciiz "Enter upper bound for z\n"
prompt_msg_UBoundZ_val: .asciiz "Lower bound for z = %d\n"
zU: .word64 0
prompt_msgAns: .asciiz "x = %d, y = %d, z = %d\n"
.word64 0
.word64 0
.word64 0
xyL_Len: .word64 0
xyU_Len: .word64 0
zU_Len: .word64 0
xyL_text: .space 32
xyU_text: .space 32
zU_text: .space 32
ZeroCode: .word64 0x30 ;Ascii '0'
.text
main: daddi r4, r0, prompt_msg_LBound
jal print_string
daddi r8, r0, xyL_text ;r8 = xyL_text
daddi r14, r0, params_sys3
daddi r9, r0, 32
jal read_keyboard_input
sd r1, xyL_Len(r0) ;save first number length
ld r10, xyL_Len(r0) ;n = r10 = length of xyL_text
daddi r17, r0, xyL_text
jal convert_string_to_integer ;r17 = &source string,r10 = string length,returns computed number in r11
sd r11, xyL(r0)
daddi r4, r0, prompt_msg_LBound_val
jal print_string
end: syscall 0
print_string: sw $a0, params_sys5(r0)
daddi r14, r0, params_sys5
syscall 5
jr r31
read_keyboard_input: sd r0, 0(r14) ;read from keyboard
sd r8, 8(r14) ;destination address
sd r9, 16(r14) ;destination size
syscall 3
jr r31
convert_string_to_integer: daddi r13, r0, 1 ;r13 = constant 1
daddi r20, r0, 10 ;r20 = constant 10
movz r11, r0, r0 ;x1 = r11 = 0
ld r19, ZeroCode(r0)
For1: beq r10, r0, EndFor1
dmultu r11, r20 ;lo = x * 10
mflo r11 ;x = r11 = lo = r11 * 10
movz r16, r0, r0 ;r16 = 0
lbu r16, 0(r17) ;r16 = text[i]
dsub r16, r16, r19 ;r16 = text[i] - '0'
dadd r11, r11, r16 ;x = x + text[i] - '0'
dsub r10, r10, r13 ;n--
dadd r17, r17, r13 ;i++
b For1
EndFor1: jr r31
我正在尝试获取第一个数字，即x，y的下限。
例如，我键入数字5，所以最后xyL表示为5，但打印的字符串为：
Enter lower bound for x,y
Lower bound for x,y = 0
如何打印输入的值，然后对下一个字符串进行打印？
谢谢。
编辑：========================================= ===========================
我通过添加另一种数据类型.data来保存地址，从而更改了.space 8，现在，我调用print_string而不是跳转到syscall 5来打印值，例如： / p>
prompt_msg_LBound: .asciiz "Enter lower bound for x,y\n"
prompt_msg_LBound_val: .asciiz "Lower bound for x,y = %d\n"
LBound_val_addr: .space 8
xyL: .space 8
以及.code部分：
sd r11, xyL(r0)
daddi r5, r0, prompt_msg_LBound_val
sd r5, LBound_val_addr(r0)
daddi r14 ,r0, LBound_val_addr
syscall 5
但是我仍然想使用print_string来打印带有用户输入值的字符串：prompt_msg_LBound_val。
我该怎么做？
答案 0 :(得分：1)
手册中的print_string示例函数并不用于占位符，只能用于纯字符串。
如果将占位符添加到格式字符串，则SYSCALL 5将继续从内存中读取那些占位符的值。在这种情况下，它只读取并显示值0，这是偶然的内存中的值。
请参见手册中的printf()示例（稍作更新和注释）以检查如何使用占位符：
.data
format_str: .asciiz "%dth of %s:\n%s version %i.%i.%i is being tested!"
s1: .asciiz "February"
s2: .asciiz "EduMIPS64"
fs_addr: .space 4 ; Will store the address of the format string
.word 10 ; The literal value 10.
s1_addr: .space 4 ; Will store the address of the string "February"
s2_addr: .space 4 ; Will store the address of the string "EduMIPS64"
.word 1 ; The literal value 1.
.word 2 ; The literal value 2.
.word 6 ; The literal value 6.
test:
.code
daddi r5, r0, format_str
sw r5, fs_addr(r0)
daddi r2, r0, s1
daddi r3, r0, s2
sd r2, s1_addr(r0)
sd r3, s2_addr(r0)
daddi r14, r0, fs_addr
syscall 5
syscall 0