Add bob exercise (#75)

config.json

@@ -58,6 +58,14 @@
         "prerequisites": [],
         "difficulty": 2
       },
+      {
+        "slug": "bob",
+        "name": "Bob",
+        "uuid": "af7ec84e-d49d-4389-9cb8-725739b40fa3",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "difference-of-squares",
         "name": "Difference of Squares",

exercises/practice/bob/.docs/instructions.md

@@ -0,0 +1,19 @@
+# Instructions
+
+Your task is to determine what Bob will reply to someone when they say something to him or ask him a question.
+
+Bob only ever answers one of five things:
+
+- **"Sure."**
+  This is his response if you ask him a question, such as "How are you?"
+  The convention used for questions is that it ends with a question mark.
+- **"Whoa, chill out!"**
+  This is his answer if you YELL AT HIM.
+  The convention used for yelling is ALL CAPITAL LETTERS.
+- **"Calm down, I know what I'm doing!"**
+  This is what he says if you yell a question at him.
+- **"Fine. Be that way!"**
+  This is how he responds to silence.
+  The convention used for silence is nothing, or various combinations of whitespace characters.
+- **"Whatever."**
+  This is what he answers to anything else.

exercises/practice/bob/.docs/introduction.md

@@ -0,0 +1,10 @@
+# Introduction
+
+Bob is a [lackadaisical][] teenager.
+He likes to think that he's very cool.
+And he definitely doesn't get excited about things.
+That wouldn't be cool.
+
+When people talk to him, his responses are pretty limited.
+
+[lackadaisical]: https://www.collinsdictionary.com/dictionary/english/lackadaisical

exercises/practice/bob/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "bob.s"
+    ],
+    "test": [
+      "bob_test.c"
+    ],
+    "example": [
+      ".meta/example.s"
+    ]
+  },
+  "blurb": "Bob is a lackadaisical teenager. In conversation, his responses are very limited.",
+  "source": "Inspired by the 'Deaf Grandma' exercise in Chris Pine's Learn to Program tutorial.",
+  "source_url": "https://pine.fm/LearnToProgram/?Chapter=06"
+}

exercises/practice/bob/.meta/example.s

@@ -0,0 +1,61 @@
+.section .rodata
+sure: .string "Sure."
+whoa: .string "Whoa, chill out!"
+calm: .string "Calm down, I know what I'm doing!"
+fine: .string "Fine. Be that way!"
+whatever: .string "Whatever."
+
+.text
+.globl response
+
+/* extern const char *response(const char *hey_bob); */
+response:
+        mov     x2, #0                  /* most recent non-whitespace character */
+        mov     x3, #0                  /* count upper case */
+        mov     x4, #0                  /* count lower case */
+
+.read:
+        ldrb    w1, [x0], #1            /* load byte, with post-increment */
+        cbz     x1, .select_response
+
+        cmp     x1, #32                 /* space */
+        ble     .read
+
+        mov     x2, x1                  /* non-whitespace character */
+        sub     x1, x1, #65
+        cmp     x1, #26                 /* upper case? */
+        cinc    x3, x3, lo              /* increment on unsigned < */
+
+        sub     x1, x1, #32
+        cmp     x1, #26                 /* lower case? */
+        cinc    x4, x4, lo              /* increment on unsigned < */
+
+        b       .read
+
+.select_response:
+        cbz     x2, .silence
+
+        cbnz    x4, .not_yell           /* does the input contain lower case letters? */
+        cbz     x3, .not_yell           /* does the input contain no upper case letters? */
+
+        adrp    x3, calm
+        add     x3, x3, :lo12:calm
+        adrp    x4, whoa
+        add     x4, x4, :lo12:whoa
+        cmp     x2, #63                 /* question mark */
+        csel    x0, x3, x4, eq
+        ret
+
+.not_yell:
+        adrp    x3, sure
+        add     x3, x3, :lo12:sure
+        adrp    x4, whatever
+        add     x4, x4, :lo12:whatever
+        cmp     x2, #63                 /* question mark */
+        csel    x0, x3, x4, eq
+        ret
+
+.silence:
+        adrp    x0, fine
+        add     x0, x0, :lo12:fine
+        ret

exercises/practice/bob/.meta/tests.toml

@@ -0,0 +1,85 @@
+# 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.
+
+[e162fead-606f-437a-a166-d051915cea8e]
+description = "stating something"
+
+[73a966dc-8017-47d6-bb32-cf07d1a5fcd9]
+description = "shouting"
+
+[d6c98afd-df35-4806-b55e-2c457c3ab748]
+description = "shouting gibberish"
+
+[8a2e771d-d6f1-4e3f-b6c6-b41495556e37]
+description = "asking a question"
+
+[81080c62-4e4d-4066-b30a-48d8d76920d9]
+description = "asking a numeric question"
+
+[2a02716d-685b-4e2e-a804-2adaf281c01e]
+description = "asking gibberish"
+
+[c02f9179-ab16-4aa7-a8dc-940145c385f7]
+description = "talking forcefully"
+
+[153c0e25-9bb5-4ec5-966e-598463658bcd]
+description = "using acronyms in regular speech"
+
+[a5193c61-4a92-4f68-93e2-f554eb385ec6]
+description = "forceful question"
+
+[a20e0c54-2224-4dde-8b10-bd2cdd4f61bc]
+description = "shouting numbers"
+
+[f7bc4b92-bdff-421e-a238-ae97f230ccac]
+description = "no letters"
+
+[bb0011c5-cd52-4a5b-8bfb-a87b6283b0e2]
+description = "question with no letters"
+
+[496143c8-1c31-4c01-8a08-88427af85c66]
+description = "shouting with special characters"
+
+[e6793c1c-43bd-4b8d-bc11-499aea73925f]
+description = "shouting with no exclamation mark"
+
+[aa8097cc-c548-4951-8856-14a404dd236a]
+description = "statement containing question mark"
+
+[9bfc677d-ea3a-45f2-be44-35bc8fa3753e]
+description = "non-letters with question"
+
+[8608c508-f7de-4b17-985b-811878b3cf45]
+description = "prattling on"
+
+[bc39f7c6-f543-41be-9a43-fd1c2f753fc0]
+description = "silence"
+
+[d6c47565-372b-4b09-b1dd-c40552b8378b]
+description = "prolonged silence"
+
+[4428f28d-4100-4d85-a902-e5a78cb0ecd3]
+description = "alternate silence"
+
+[66953780-165b-4e7e-8ce3-4bcb80b6385a]
+description = "multiple line question"
+
+[5371ef75-d9ea-4103-bcfa-2da973ddec1b]
+description = "starting with whitespace"
+
+[05b304d6-f83b-46e7-81e0-4cd3ca647900]
+description = "ending with whitespace"
+
+[72bd5ad3-9b2f-4931-a988-dce1f5771de2]
+description = "other whitespace"
+
+[12983553-8601-46a8-92fa-fcaa3bc4a2a0]
+description = "non-question ending with whitespace"

exercises/practice/bob/Makefile

@@ -0,0 +1,36 @@
+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/bob/bob.s

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