Add raindrops exercise

config.json

@@ -146,6 +146,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "raindrops",
+        "name": "Raindrops",
+        "uuid": "4f701cd9-698e-4528-b3f5-18b5459d880f",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "square-root",
         "name": "Square Root",

exercises/practice/raindrops/.docs/instructions.md

@@ -0,0 +1,24 @@
+# Instructions
+
+Your task is to convert a number into its corresponding raindrop sounds.
+
+If a given number:
+
+- is divisible by 3, add "Pling" to the result.
+- is divisible by 5, add "Plang" to the result.
+- is divisible by 7, add "Plong" to the result.
+- **is not** divisible by 3, 5, or 7, the result should be the number as a string.
+
+## Examples
+
+- 28 is divisible by 7, but not 3 or 5, so the result would be `"Plong"`.
+- 30 is divisible by 3 and 5, but not 7, so the result would be `"PlingPlang"`.
+- 34 is not divisible by 3, 5, or 7, so the result would be `"34"`.
+
+~~~~exercism/note
+A common way to test if one number is evenly divisible by another is to compare the [remainder][remainder] or [modulus][modulo] to zero.
+Most languages provide operators or functions for one (or both) of these.
+
+[remainder]: https://exercism.org/docs/programming/operators/remainder
+[modulo]: https://en.wikipedia.org/wiki/Modulo_operation
+~~~~

exercises/practice/raindrops/.docs/introduction.md

@@ -0,0 +1,3 @@
+# Introduction
+
+Raindrops is a slightly more complex version of the FizzBuzz challenge, a classic interview question.

exercises/practice/raindrops/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "raindrops.s"
+    ],
+    "test": [
+      "raindrops_test.c"
+    ],
+    "example": [
+      ".meta/example.s"
+    ]
+  },
+  "blurb": "Convert a number into its corresponding raindrop sounds - Pling, Plang and Plong.",
+  "source": "A variation on FizzBuzz, a famous technical interview question that is intended to weed out potential candidates. That question is itself derived from Fizz Buzz, a popular children's game for teaching division.",
+  "source_url": "https://en.wikipedia.org/wiki/Fizz_buzz"
+}

exercises/practice/raindrops/.meta/example.s

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+.section .rodata
+pling: .string "Pling"
+plang: .string "Plang"
+plong: .string "Plong"
+
+.macro APPEND sound, factor
+        mov     x3, \factor
+        udiv    x4, x1, x3
+        msub    x5, x4, x3, x1          /* remainder */
+        cbnz    x5, .end_\sound
+
+        adrp    x4, \sound
+        add     x4, x4, :lo12:\sound
+
+.copy_\sound:
+        ldrb    w3, [x4], #1            /* load byte, with post-increment */
+        strb    w3, [x2], #1            /* store byte, post-increment */
+        cbnz    w3, .copy_\sound
+
+        sub     x2, x2, #1
+.end_\sound:
+
+.endm
+
+.text
+.globl convert
+
+/* extern void convert(char *buffer, uint64_t number); */
+convert:
+        mov     x2, x0
+        APPEND  pling, #3
+        APPEND  plang, #5
+        APPEND  plong, #7
+
+        cmp     x2, x0
+        bne     .done
+
+        mov     x3, #10
+
+.write:
+        mov     x5, x1
+        udiv    x1, x5, x3              /* divide value by 10 */
+        msub    x6, x1, x3, x5          /* remainder, i.e. output digit */
+        add     w6, w6, #48             /* '0' */
+        strb    w6, [x2], #1            /* store, post-increment */
+        cbnz    x1, .write              /* loop until value is 0 */
+
+        strb    wzr, [x2]               /* store null terminator */
+
+.reverse:
+        sub     x2, x2, #1
+        cmp     x2, x0
+        beq     .done                   /* middle byte of odd length string */
+
+        ldrb    w4, [x2]
+        ldrb    w3, [x0]
+        strb    w3, [x2]
+        strb    w4, [x0], #1            /* store byte, post-increment */
+        cmp     x2, x0
+        bne     .reverse
+                                        /* middle bytes of even length string */
+
+.done:
+        ret

exercises/practice/raindrops/.meta/tests.toml

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+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[1575d549-e502-46d4-a8e1-6b7bec6123d8]
+description = "the sound for 1 is 1"
+
+[1f51a9f9-4895-4539-b182-d7b0a5ab2913]
+description = "the sound for 3 is Pling"
+
+[2d9bfae5-2b21-4bcd-9629-c8c0e388f3e0]
+description = "the sound for 5 is Plang"
+
+[d7e60daa-32ef-4c23-b688-2abff46c4806]
+description = "the sound for 7 is Plong"
+
+[6bb4947b-a724-430c-923f-f0dc3d62e56a]
+description = "the sound for 6 is Pling as it has a factor 3"
+
+[ce51e0e8-d9d4-446d-9949-96eac4458c2d]
+description = "2 to the power 3 does not make a raindrop sound as 3 is the exponent not the base"
+
+[0dd66175-e3e2-47fc-8750-d01739856671]
+description = "the sound for 9 is Pling as it has a factor 3"
+
+[022c44d3-2182-4471-95d7-c575af225c96]
+description = "the sound for 10 is Plang as it has a factor 5"
+
+[37ab74db-fed3-40ff-b7b9-04acdfea8edf]
+description = "the sound for 14 is Plong as it has a factor of 7"
+
+[31f92999-6afb-40ee-9aa4-6d15e3334d0f]
+description = "the sound for 15 is PlingPlang as it has factors 3 and 5"
+
+[ff9bb95d-6361-4602-be2c-653fe5239b54]
+description = "the sound for 21 is PlingPlong as it has factors 3 and 7"
+
+[d2e75317-b72e-40ab-8a64-6734a21dece1]
+description = "the sound for 25 is Plang as it has a factor 5"
+
+[a09c4c58-c662-4e32-97fe-f1501ef7125c]
+description = "the sound for 27 is Pling as it has a factor 3"
+
+[bdf061de-8564-4899-a843-14b48b722789]
+description = "the sound for 35 is PlangPlong as it has factors 5 and 7"
+
+[c4680bee-69ba-439d-99b5-70c5fd1a7a83]
+description = "the sound for 49 is Plong as it has a factor 7"
+
+[17f2bc9a-b65a-4d23-8ccd-266e8c271444]
+description = "the sound for 52 is 52"
+
+[e46677ed-ff1a-419f-a740-5c713d2830e4]
+description = "the sound for 105 is PlingPlangPlong as it has factors 3, 5 and 7"
+
+[13c6837a-0fcd-4b86-a0eb-20572f7deb0b]
+description = "the sound for 3125 is Plang as it has a factor 5"

exercises/practice/raindrops/Makefile

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+AS = aarch64-linux-gnu-as
+CC = aarch64-linux-gnu-gcc
+
+CFLAGS = -g -Wall -Wextra -pedantic -Werror
+LDFLAGS =
+
+ALL_LDFLAGS = -pie -Wl,--fatal-warnings
+
+ALL_CFLAGS = -std=c99 -fPIE $(CFLAGS)
+ALL_LDFLAGS += $(LDFLAGS)
+
+C_OBJS = $(patsubst %.c,%.o,$(wildcard *.c))
+AS_OBJS = $(patsubst %.s,%.o,$(wildcard *.s))
+ALL_OBJS = $(filter-out example.o,$(C_OBJS) $(AS_OBJS) vendor/unity.o)
+
+CC_CMD = $(CC) $(ALL_CFLAGS) -c -o $@ $<
+
+all: tests
+	qemu-aarch64 -L /usr/aarch64-linux-gnu ./$<
+
+tests: $(ALL_OBJS)
+	@$(CC) $(ALL_CFLAGS) $(ALL_LDFLAGS) -o $@ $(ALL_OBJS)
+
+%.o: %.s
+	@$(AS) -o $@ $<
+
+%.o: %.c
+	@$(CC_CMD)
+
+vendor/unity.o: vendor/unity.c vendor/unity.h vendor/unity_internals.h
+	@$(CC_CMD)
+
+clean:
+	@rm -f *.o vendor/*.o tests
+
+.PHONY: all clean

exercises/practice/raindrops/raindrops.s

@@ -0,0 +1,5 @@
+.text
+.globl convert
+
+convert:
+    ret