From fdb9277ad186ffc1d0255d2b2f4c43aa778a01b6 Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Tue, 8 Dec 2020 15:16:00 +0000
Subject: [PATCH] day8

i wanna die
---
 day8/Makefile |  50 ++++++++++++++++
 day8/day8.c   | 162 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 212 insertions(+)
 create mode 100644 day8/Makefile
 create mode 100644 day8/day8.c

diff --git a/day8/Makefile b/day8/Makefile
new file mode 100644
index 0000000..5eace09
--- /dev/null
+++ b/day8/Makefile
@@ -0,0 +1,50 @@
+
+OPT_FLAGS?= -march=native -flto \
+	 -march=native -fgraphite -fopenmp -floop-parallelize-all -ftree-parallelize-loops=4 \
+	 -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block \
+	 -fno-stack-check -fno-strict-aliasing 
+
+INCLUDE?=../common/include
+
+COMMON_FLAGS?=-pipe -O3 -Wall -pedantic -Wextra -Wstrict-aliasing 
+
+C_OPT_FLAGS=$(OPT_FLAGS)
+CXX_OPT_FLAGS=$(OPT_FLAGS) -felide-constructors -fno-exceptions
+LD_OPT_FLAGS?=-O3 -flto
+
+
+CFLAGS?=$(COMMON_FLAGS) $(C_OPT_FLAGS) --std=gnu11
+CXXFLAG?+=$(COMMON_FLAGS) $(CXX_OPT_FLAGS) --std=gnu++20
+LDFLAGS?=$(LD_OPT_FLAGS)
+
+CFLAGS+=-I$(INCLUDE)
+
+.PHONY: all
+all: part1 part2
+
+.PHONY: test
+test: part1-test part2-test
+
+inpu%.h: inpu%
+	@rm -f $@
+	while read line; do \
+		echo "\"$$line\"," >> $@; \
+	done < $<
+
+part1: day8.c | input.h
+	$(CC) $< $(CFLAGS) -o $@ $(LDFLAGS)
+	strip $@
+
+part2: day8.c | input.h
+	$(CC) $< -DPART2 $(CFLAGS) -o $@ $(LDFLAGS)
+	strip $@
+
+part1-test: day8.c | input-test.h
+	$(CC) $< -DTEST $(CFLAGS) -o $@ $(LDFLAGS)
+
+part2-test: day8.c | input-test.h
+	$(CC) $< -DPART2 -DTEST $(CFLAGS) -o $@ $(LDFLAGS)
+
+clean:
+	rm -f part{1,2}{,-test}
+	rm -f input{,-test}.h
diff --git a/day8/day8.c b/day8/day8.c
new file mode 100644
index 0000000..a7c0f6b
--- /dev/null
+++ b/day8/day8.c
@@ -0,0 +1,162 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <attrs.h>
+#include <panic.h>
+
+const char* const input[] = {
+#ifdef TEST
+#include "input-test.h"
+#else
+#include "input.h"
+#endif
+};
+
+#define input_sz (sizeof(input)/sizeof(char*))
+
+enum op {
+	OP_NOP=0, 
+	OP_ACC,
+	OP_JMP,
+	OP_HLT,
+};
+
+inline static const char* strop(enum op op)
+{
+	switch(op) {
+		case OP_NOP: return "nop";
+		case OP_ACC: return "acc";
+		case OP_JMP: return "jmp";
+		case OP_HLT: return "hlt";
+	}
+	panic("Unknown op %d", op);
+}
+
+enum exec_stat {
+	END = 0,
+	HALT,
+};
+
+typedef struct instr {
+	enum op operator;
+	int64_t operand;
+} instruction_t;
+
+struct reg {
+	ssize_t pc;
+	int64_t acc;
+	int pjmp[input_sz];
+};
+
+
+static pure instruction_t parse_single(const char* str)
+{
+	register instruction_t op;
+	switch(str[0]) {
+		case 'n': op.operator = OP_NOP; break;
+		case 'a': op.operator = OP_ACC; break;
+		case 'j': op.operator = OP_JMP; break;
+		default: panic("Unknown instr op: %s", str);
+	}
+	op.operand = (int64_t)atoll(str+4);
+	return op;
+}
+
+enum exec_stat execute_destructive(instruction_t* restrict prog, struct reg* restrict reg, size_t len);
+
+enum exec_stat execute(const instruction_t* prog, struct reg* restrict reg)
+{
+	instruction_t dest[input_sz];
+	memcpy(dest, prog, input_sz * sizeof(prog[0]));
+	reg->pc = 0;
+	reg->acc =0;
+	return execute_destructive(dest, reg, input_sz);
+}
+enum exec_stat execute_destructive(instruction_t* restrict prog, struct reg* restrict reg, size_t len)
+{
+	for(;(size_t)reg->pc<len;)
+	{
+		if(reg->pc < 0) panic("Invalid pc %ld", reg->pc);
+
+		instruction_t* restrict current = &prog[reg->pc];
+		enum op op = current->operator;
+		current->operator = OP_HLT;
+		switch(op)
+		{
+			case OP_HLT: return HALT;
+			case OP_JMP: 
+				reg->pc += (ssize_t)current->operand;
+				continue;
+			case OP_ACC: reg->acc += current->operand; break;
+			default: break;
+		}
+		reg->pc += 1;
+	}
+
+	return END;
+}
+
+void swap(size_t* restrict s1, size_t* restrict s2)
+{
+	*s1 = *s1 ^ *s2;
+	*s2 = *s1 ^ *s2;
+	*s1 = *s1 ^ *s2;
+}
+
+void reverse(size_t* restrict ar, size_t len)
+{
+	size_t i=0,j=len-1;
+	if(j==1) return;
+	while(i<j) {
+		
+		swap(ar+i, ar+j);
+		i++; j--;
+	}
+}
+
+int main()
+{
+	instruction_t instr[input_sz];
+	size_t jumps[input_sz]; size_t nj =0;
+	size_t nops[input_sz]; size_t ni=0;
+	for (size_t i=0;i<input_sz;i++) {
+		switch((instr[i] = parse_single(input[i])).operator)
+		{
+			case OP_NOP: nops[ni++] = i; break;
+			case OP_JMP: jumps[nj++] = i; break;
+			default: break;
+		}
+	}
+	reverse(jumps, nj);
+	reverse(nops, ni);
+	
+	struct reg state = {0};
+#ifdef PART2
+	register int seti=0,setj=0;
+	while (execute(instr, &state)) {
+		if(seti)instr[nops [ni]].operator = OP_NOP;
+		if(setj)instr[jumps[nj]].operator = OP_JMP;
+		
+		seti=setj=0;
+		if(ni) {
+			instr[nops [--ni]].operator = OP_JMP;
+			seti=1;
+		}
+		else if(nj) {
+			instr[jumps[--nj]].operator = OP_NOP;
+			setj=1;
+		}
+		else panic("All inputs halt: %ld", state.acc);
+#ifdef DEBUG
+		fprintf(stderr, "Retry: %ld %ld\n", state.pc, state.acc);
+#endif
+	}
+#else
+	enum exec_stat res = execute_destructive(instr, &state, input_sz);
+	if(!res) panic("No halt");	
+#endif
+	printf("%ld\n", state.acc);
+	return 0;
+}
+