[Sync Track] arm64-assembly

solutions/arm64-assembly/acronym/1/acronym.s

@@ -0,0 +1,33 @@
+// For Shree DR.MDD
+
+.text
+.globl abbreviate
+
+abbreviate:
+        ldrb    w5, [x1], #1            /* load byte, post-increment */
+        cbz     w5, .done_abbrev
+
+        and     w6, w5, #-33            /* force upper case */
+        sub     w7, w6, #'A'
+        cmp     w7, #26
+        bhs     abbreviate               /* jump if word has not yet started */
+
+        strb    w6, [x0], #1            /* store byte, post-increment */
+
+.scan_word:
+        ldrb    w5, [x1], #1            /* load next byte */
+        cbz     w5, .done_abbrev
+
+        cmp     w5, #'\''                /* check for apostrophe */
+        beq     .scan_word
+
+        and     w6, w5, #-33             /* force upper case */
+        sub     w7, w6, #'A'
+        cmp     w7, #26
+        blo     .scan_word                /* keep scanning if letter */
+
+        b       abbreviate                /* move to next word */
+
+.done_abbrev:
+        strb    wzr, [x0]                /* null-terminate output */
+        ret

solutions/arm64-assembly/affine-cipher/1/affine_cipher.s

@@ -0,0 +1,68 @@
+// Dedicated to Shree DR.MDD
+
+.data
+inverses: .byte 0, 1, 0, 9, 0, 21, 0, 15, 0, 3, 0, 19, 0, 0, 0, 7, 0, 23, 0, 11, 0, 5, 0, 17, 0, 25
+
+.text
+.globl encode
+.globl decode
+
+encode:
+        adrp    x14, inverses
+        add     x14, x14, :lo12:inverses
+        ldrb    w11, [x14, x2]
+        cbz     w11, finish
+
+        mov     w11, w2
+        mov     w12, w3
+        mov     x2, #5
+        b       cipher_loop
+
+decode:
+        adrp    x14, inverses
+        add     x14, x14, :lo12:inverses
+        ldrb    w11, [x14, x2]
+        cbz     w11, finish
+
+        sub     w12, w3, #4082
+        mneg    w12, w12, w11
+        mov     x2, #-1
+        b       cipher_loop
+
+finish:
+        strb    wzr, [x0]
+        ret
+
+cipher_loop:
+        mov     x13, x2
+        mov     w8, #' '
+        mov     w9, #26
+
+input_read:
+        ldrb    w5, [x1], #1
+        cbz     w5, finish
+
+        sub     w10, w5, #'0'
+        cmp     w10, #10
+        blo     .process_char
+
+        orr     w10, w5, #32
+        sub     w10, w10, #'a'
+        cmp     w10, w9
+        bhs     input_read
+
+        madd    w10, w11, w10, w12
+        udiv    w15, w10, w9
+        msub    w5, w15, w9, w10
+        add     w5, w5, #'a'
+
+.process_char:
+        cbnz    x13, .store_char
+
+        strb    w8, [x0], #1
+        mov     x13, x2
+
+.store_char:
+        strb    w5, [x0], #1
+        sub     x13, x13, 1
+        b       input_read

solutions/arm64-assembly/all-your-base/1/all_your_base.s

@@ -0,0 +1,60 @@
+.equ BAD_BASE, -1
+.equ BAD_DIGIT, -2
+
+.text
+.globl rebase
+
+rebase:
+        cmp w0,#1
+        b.le badbase
+        cmp w3,#1
+        b.le badbase
+        eor x6,x6,x6
+inbaseloop:
+        cbz x2,outbase
+        ldr w5,[x1],#4
+        cmp w5,#0
+        b.lt baddigit
+        cmp w5,w0
+        b.ge baddigit
+        madd w6,w6,w0,w5
+        sub x2,x2,#1
+        b.al inbaseloop
+outbase:
+        mov x5,#0
+        eor x9,x9,x9
+outbaseloop:
+        add x5,x5,#1
+        udiv x7,x6,x3
+        msub x8,x7,x3,x6
+        str  w8,[x4,x9]
+        cbz x7,reverse
+        mov x6,x7
+        add x9,x9,#4
+        b.al outbaseloop
+reverse:
+        lsl x9,x5,#2
+        sub x9,x9,#4
+        eor x6,x6,x6
+        mov x10,x5
+        lsr x5,x5,#1        
+        cbz x5,endofproc
+reverseloop:
+        ldr w7,[x4,x6]
+        ldr w8,[x4,x9]
+        str w7,[x4,x9]
+        str w8,[x4,x6]
+        add x6,x6,#4
+        sub x9,x9,#4
+        sub x5,x5,#1
+        cbnz x5,reverseloop
+endofproc:
+        mov x0,x10
+        ret
+badbase:
+        mov x0,BAD_BASE
+        ret
+baddigit:
+        mov x0,BAD_DIGIT
+        ret
+

solutions/arm64-assembly/allergies/1/allergies.s

@@ -0,0 +1,39 @@
+.text
+.equ MAX_ITEMS, 8
+
+.globl allergic_to
+.globl list
+
+allergic_to:
+    mov   x2, #1
+    lsl   x2, x2, x0
+    and   x0, x2, x1
+    ret
+
+list:
+    mov   x3, xzr
+    and   x0, x0, #0xFF
+    cbz   x0, .return
+
+    mov   x2, xzr
+    mov   x4, #1
+
+.next:
+    cmp   x2, #MAX_ITEMS
+    beq   .return
+    lsl   x5, x4, x2
+    and   x6, x0, x5
+    cbnz  x6, .add
+    add   x2, x2, #1
+    b     .next
+
+.add:
+    add   x3, x3, #1
+    lsl   x6, x3, #2
+    str   w2, [x1, x6]
+    add   x2, x2, #1
+    b     .next
+
+.return:
+    str   w3, [x1]
+    ret

solutions/arm64-assembly/anagram/1/anagram.s

@@ -0,0 +1,86 @@
+.text
+.globl find_anagrams
+
+find_anagrams:
+        eor x5,x5,x5
+mainloop1:
+        ldrb w4,[x3,x5]
+        cbz w4,addcandidatemaybe
+        cmp w4,'A'
+        b.lt lower1
+        cmp w4,'Z'
+        b.gt lower1
+        add w4,w4,32
+lower1:
+        eor x8,x8,x8
+        eor x9,x9,x9
+        mov x6,x3
+innerloop2:
+        ldrb w7,[x6],#1
+        cbz w7,endofinner2
+        cmp w7,'A'
+        b.lt lower2
+        cmp w7,'Z'
+        b.gt lower2
+        add w7,w7,32
+lower2: 
+        cmp w4,w7
+        b.ne notequal2
+        add x8,x8,#1
+notequal2:
+        add x9,x9,#1
+        b.al innerloop2
+endofinner2:
+        ldr x6,[x1]
+innerloop3:
+        ldrb w7,[x6],#1
+        cbz w7,endofinner3 
+        cmp w7,'A'
+        b.lt lower3
+        cmp w7,'Z'
+        b.gt lower3
+        add w7,w7,32
+lower3:
+        cmp w4,w7
+        b.ne notequal3
+        sub x8,x8,#1
+notequal3:
+        sub x9,x9,#1
+        b.al innerloop3
+endofinner3:
+        eor x4,x4,x4
+        cbnz x8, donotadd
+        cbnz x9, donotadd
+        add x5,x5,#1
+        b.al mainloop1
+addcandidatemaybe:
+        eor x5,x5,x5
+        ldr x6,[x1]
+cmploop:
+        ldrb w4, [x3, x5]
+        cbz  w4,donotadd
+        ldrb w7, [x6, x5]
+        cmp w4,'A'
+        b.lt lower4
+        cmp w4,'Z'
+        b.gt lower4
+        add w4,w4,32
+lower4:
+        cmp w7,'A'
+        b.lt lower5
+        cmp w7,'Z'
+        b.gt lower5
+        add w7,w7,32
+lower5: 
+        add x5,x5,#1
+        cmp w4,w7
+        b.eq cmploop
+addcandidate:
+        mov x4,#1
+donotadd:
+        eor x5,x5,x5
+        str w4,[x0],#4
+        add x1,x1,#8
+        sub x2,x2,#1
+        cbnz x2,mainloop1
+        ret

solutions/arm64-assembly/armstrong-numbers/1/armstrong_numbers.s

@@ -0,0 +1,40 @@
+// Dedicated to Shree DR.MDD
+
+.text
+.globl is_armstrong_number
+
+is_armstrong_number:
+        mov     x1, #10
+        mov     x8, x0                  /* number */
+        mov     x11, xzr                 /* digit count */
+        mov     x12, xzr                 /* sum of digit powers */
+
+.count_digits_loop:
+        add     x11, x11, #1
+        udiv    x0, x0, x1
+        cbnz    x0, .count_digits_loop
+
+        mov     x0, x8
+
+.extract_loop:
+        udiv    x2, x0, x1
+        msub    x3, x2, x1, x0
+        mov     x0, x2
+        mov     x13, #1
+        mov     x14, x11
+
+.power_loop:
+        mul     x7, x13, x3
+        tst     x14, #1
+        csel    x13, x7, x13, ne
+
+        mul     x3, x3, x3
+        lsr     x14, x14, #1
+        cbnz    x14, .power_loop
+
+        add     x12, x12, x13
+        cbnz    x2, .extract_loop
+
+        cmp     x12, x8
+        cset    x0, eq
+        ret

solutions/arm64-assembly/atbash-cipher/1/atbash_cipher.s

@@ -0,0 +1,51 @@
+// Dedicated to Shree DR.MDD
+
+.text
+.globl encode
+.globl decode
+
+encode:
+        mov     x9, #5
+        b       core_process
+        ret
+
+decode:
+        mov     x9, #-1
+        b       core_process
+
+core_process:
+        mov     x10, x9
+        mov     w14, #' '
+        mov     w15, #'z'
+
+read_loop:
+        ldrb    w12, [x1], #1
+        cbz     w12, end_loop
+
+        sub     w13, w12, #'0'
+        cmp     w13, #10
+        blo     accept_char
+
+        orr     w13, w12, #32
+        sub     w13, w13, #'a'
+        cmp     w13, #26
+        bhs     read_loop
+
+        sub     w13, w15, w13
+        and     w12, w12, #32
+        orr     w12, w12, w13
+
+accept_char:
+        cbnz    x10, write_char
+
+        strb    w14, [x0], #1
+        mov     x10, x9
+
+write_char:
+        strb    w12, [x0], #1
+        sub     x10, x10, 1
+        b       read_loop
+
+end_loop:
+        strb    w12, [x0]
+        ret