diff options
Diffstat (limited to 'mips/chapter-3/exercise-7.s')
| -rw-r--r-- | mips/chapter-3/exercise-7.s | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/mips/chapter-3/exercise-7.s b/mips/chapter-3/exercise-7.s new file mode 100644 index 0000000..924765d --- /dev/null +++ b/mips/chapter-3/exercise-7.s @@ -0,0 +1,47 @@ +# print(hex(0b11001)) + .text +main: + li $t0, 25 # t0 = 0b11001 + li $t1, 0 # t1 = 0 + li $t9, 9 # t9 = 9 + +reverse: + beqz $t0, done # if (!t0) goto done + andi $t2, $t0, 0xf # t2 = t0 & 0xf + sra $t0, $t0, 4 # t0 >>= 4 + sll $t1, $t1, 4 # t1 <<= 4 + add $t1, $t1, $t2 # t1 += t2 + j reverse # goto reverse +done: + + li $v0, 11 # print character + li $a0, 48 # 0 + syscall + li $v0, 11 # print character + li $a0, 120 # x + syscall + bnez $t1, print # if (!t1) goto print + li $v0, 11 # print character + li $a0, 48 # 0 + syscall + j end # goto end + +print: + beqz $t1, end # if (!t1) goto end + andi $t2, $t1, 0xf # t2 = t1 & 0xf + sra $t1, $t1, 4 # t1 >>= 4 + addi $a0, $t2, 48 # a0 = chr(t2), sort of + ble $t2, $t9, put # if (t2 <= 9) goto put + addi $a0, $a0, 7 # a0 += 7 +put: + li $v0, 11 # print character at a0 + syscall + j print # goto print +end: + + li $v0, 11 # print character + li $a0, 10 # newline + syscall + + li $v0, 10 # terminate + syscall |