15 files changed, 1091 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a1899e9
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+deps.mk
+docs/output
+build
+ejit.o
+examples/exec
+examples/*.d
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..a514045
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "deps/lightening"]
+	path = deps/lightening
+	url = https://gitlab.com/Kimplul/lightening.git
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..839fd5f
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,60 @@
+.PHONY: all
+all: setup
+	$(MAKE) -f scripts/makefile
+
+.PHONY: examples
+examples: setup
+	$(MAKE) -f scripts/makefile examples
+
+# this kicks all unrecognised targets to the client script.
+# note that trying to compile individual files, e.g.
+#
+#	make kernel.elf
+#
+# will not work, you would need
+#
+#	make -f scripts/makefile kernel.elf
+#
+# instead
+.DEFAULT: setup
+	$(MAKE) -f scripts/makefile $<
+
+.PHONY:
+setup:
+	@echo -n > deps.mk
+	@./scripts/gen-deps -p EJIT -c COMPILE_EJIT -b ejit "$(EJIT_SOURCES)"
+
+CLEANUP		:= build deps.mk ejit.o examples/exec examples/*.d
+CLEANUP_CMD	:=
+EJIT_SOURCES	:=
+
+include src/source.mk
+
+.PHONY: format
+format:
+	find src include -iname '*.[ch]' |\
+		xargs uncrustify -c uncrustify.conf --no-backup -F -
+
+.PHONY: license
+license:
+	find src include -iname '*.[ch]' |\
+		xargs ./scripts/license
+
+.PHONY: docs
+docs:
+	find src include -iname '*.[ch]' -not -path */gen/* |\
+		xargs ./scripts/warn-undocumented
+	doxygen docs/doxygen.conf
+
+RM	= rm
+
+.PHONY: clean
+clean:
+	$(RM) -rf $(CLEANUP)
+
+.PHONY: clean_docs
+clean_docs:
+	$(RM) -rf docs/output
+
+.PHONY: clean_all
+clean_all: clean clean_docs
diff --git a/deps/lightening b/deps/lightening
new file mode 160000
+Subproject 4f1aa83d2cb0cc882790ea578828efe72df5ff1
diff --git a/examples/main.c b/examples/main.c
new file mode 100644
index 0000000..d33ed10
--- /dev/null
+++ b/examples/main.c
@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include "../include/ejit/ejit.h"
+
+int main()
+{
+	struct ejit_func *f = ejit_create_func(EJIT_INT64, 0, NULL);
+
+	ejit_movi(f, EJIT_GPR(3), 1); // location 3 just has a constant 1 for
+				      // increment
+	ejit_movi(f, EJIT_GPR(2), 0); // location 2 is i = 0
+	ejit_movi(f, EJIT_GPR(1), 1000000000); // location 1 is limit = one billion
+	ejit_movi(f, EJIT_GPR(0), 0); // location 0 is total = 0
+
+	struct ejit_label l = ejit_label(f); // top
+	ejit_addr(f, EJIT_GPR(0), EJIT_GPR(0), EJIT_GPR(2)); // add i to total
+	ejit_addr(f, EJIT_GPR(2), EJIT_GPR(2), EJIT_GPR(3)); // add 1 to i
+	struct ejit_reloc r = ejit_bltr(f, EJIT_GPR(2), EJIT_GPR(1)); // if i is less than limit
+
+	ejit_ret(f, EJIT_GPR(0)); // return total
+
+	ejit_patch(f, r, l);
+
+	/* the highest location we used was 3, so we need to request 3 location
+	 * for general purpose registers in total. No floating point registers,
+	 * so 0. */
+	ejit_compile_func(f, 4, 0);
+	long result = ejit_run_func(f, 0, NULL); // no args so this is fine
+	printf("%ld\n", result);
+
+	ejit_destroy_func(f);
+	return 0;
+}
diff --git a/include/ejit/ejit.h b/include/ejit/ejit.h
new file mode 100644
index 0000000..56582be
--- /dev/null
+++ b/include/ejit/ejit.h
@@ -0,0 +1,256 @@
+#ifndef EJIT_H
+#define EJIT_H
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <stdbool.h>
+
+enum ejit_type
+{
+	/* special case, only to be used to indicate return value of function */
+	EJIT_VOID,
+	/* free to use wherever */
+	EJIT_UINT8,
+	EJIT_INT8,
+	EJIT_UINT16,
+	EJIT_INT16,
+	EJIT_UINT32,
+	EJIT_INT32,
+	EJIT_UINT64,
+	EJIT_INT64,
+	EJIT_POINTER,
+	EJIT_FLOAT,
+	EJIT_DOUBLE,
+};
+
+struct ejit_arg {
+	union {
+		int8_t c;
+		uint8_t uc;
+		int16_t s;
+		uint16_t us;
+		int32_t i;
+		uint32_t ui;
+		int64_t l;
+		uint64_t ul;
+		float f;
+		double d;
+		void *p;
+	};
+	enum ejit_type type;
+};
+
+static inline bool ejit_int_type(enum ejit_type t)
+{
+	switch (t) {
+	case EJIT_INT8:
+	case EJIT_INT16:
+	case EJIT_INT32:
+	case EJIT_INT64:
+	case EJIT_UINT8:
+	case EJIT_UINT16:
+	case EJIT_UINT32:
+	case EJIT_UINT64:
+	case EJIT_POINTER:
+		return true;
+	default:
+	}
+
+	return false;
+}
+
+static inline bool ejit_float_type(enum ejit_type t)
+{
+	switch (t) {
+	case EJIT_FLOAT:
+	case EJIT_DOUBLE:
+		return true;
+	default:
+	}
+
+	return false;
+}
+
+static inline struct ejit_arg ejit_build_arg(enum ejit_type type, long x)
+{
+	assert(ejit_int_type(type));
+
+	struct ejit_arg a;
+	a.type = type;
+
+	switch (type) {
+	case EJIT_INT8: a.c = x; break;
+	case EJIT_INT16: a.s = x; break;
+	case EJIT_INT32: a.i = x; break;
+	case EJIT_INT64: a.l = x; break;
+	case EJIT_UINT8: a.uc = x; break;
+	case EJIT_UINT16: a.us = x; break;
+	case EJIT_UINT32: a.ui = x; break;
+	case EJIT_UINT64: a.ul = x; break;
+	case EJIT_POINTER: a.p = (void *)x; break;
+	default: abort();
+	}
+
+	return a;
+}
+
+static inline struct ejit_arg ejit_build_arg_f(enum ejit_type type, double x)
+{
+	assert(ejit_float_type(type));
+
+	struct ejit_arg a;
+	a.type = type;
+
+	switch (type) {
+	case EJIT_FLOAT: a.f = x; break;
+	case EJIT_DOUBLE: a.d = x; break;
+	default: abort();
+	}
+
+	return a;
+}
+
+#define EJIT_C(x) ((struct ejit_arg){.c = (int8_t)(x), .type = EJIT_INT8})
+
+/* register allocator could be just pushing everything above V0 or whatever onto
+ * the stack, heh */
+struct ejit_gpr {
+	size_t r;
+};
+
+struct ejit_fpr {
+	size_t f;
+};
+
+struct ejit_reloc {
+	size_t insn;
+};
+
+struct ejit_label {
+	size_t addr;
+};
+
+struct ejit_operand {
+	enum {
+		EJIT_OPERAND_GPR,
+		EJIT_OPERAND_FPR,
+		EJIT_OPERAND_IMM,
+		EJIT_OPERAND_FLT,
+	} kind;
+
+	enum ejit_type type;
+
+	union {
+	long r;
+	double d;
+	};
+};
+
+struct ejit_func;
+
+struct ejit_func *ejit_create_func(enum ejit_type rtype, size_t argc, const struct ejit_operand args[argc]);
+void ejit_compile_func(struct ejit_func *f, size_t gpr, size_t fpr);
+long ejit_run_func(struct ejit_func *f, size_t argc, struct ejit_arg args[argc]);
+double ejit_run_func_f(struct ejit_func *f, size_t argc, struct ejit_arg args[argc]);
+
+void ejit_destroy_func(struct ejit_func *s);
+
+#define EJIT_GPR(x) ((struct ejit_gpr){.r = (x)})
+#define EJIT_FPR(x) ((struct ejit_fpr){.f = (x)})
+
+#define EJIT_OPERAND_GPR(x, type) (struct ejit_operand { .kind = EJIT_OPERAND_GPR, .r = (long)(x), .type = (type)})
+#define EJIT_OPERAND_FPR(x, type) (struct ejit_operand { .kind = EJIT_OPERAND_FPR, .r = (long)(x)})
+#define EJIT_OPERAND_IMM(x, type) (struct ejit_operand { .kind = EJIT_OPERAND_IMM, .r = (long)(x)})
+#define EJIT_OPERAND_FLT(x, type) (struct ejit_operand { .kind = EJIT_OPERAND_FLT, .r = (double)(x)})
+
+typedef long (*ejit_escape_t)(size_t argc, const struct ejit_arg args[argc]);
+typedef double (*ejit_escape_f_t)(size_t argc, const struct ejit_arg args[argc]);
+
+struct ejit_label ejit_label(struct ejit_func *s);
+
+void ejit_calli(struct ejit_func *s, struct ejit_func *f, size_t argc, const struct ejit_operand args[argc]);
+
+void ejit_calli_f(struct ejit_func *s, struct ejit_func *f, size_t argc, const struct ejit_operand args[argc]);
+
+void ejit_escapei(struct ejit_func *s, ejit_escape_t f, size_t argc, const struct ejit_operand args[argc]);
+
+void ejit_escapei_f(struct ejit_func *s, ejit_escape_f_t f, size_t argc, const struct ejit_operand args[argc]);
+
+void ejit_ret(struct ejit_func *s, struct ejit_gpr r0);
+void ejit_ret_f(struct ejit_func *s, struct ejit_fpr r0);
+void ejit_ret_i(struct ejit_func *s, long i);
+void ejit_ret_fi(struct ejit_func *s, double f);
+
+/* move from r1 to r0 */
+void ejit_movi(struct ejit_func *s, struct ejit_gpr r0, long i);
+void ejit_movr(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1);
+void ejit_movr_d(struct ejit_func *s, struct ejit_fpr r0, struct ejit_fpr r1);
+
+void ejit_ldi_8(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_ldi_16(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_ldi_32(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_ldi_64(struct ejit_func *s, struct ejit_gpr r0, void *p);
+
+void ejit_ldi_u8(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_ldi_u16(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_ldi_u32(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_ldi_u64(struct ejit_func *s, struct ejit_gpr r0, void *p);
+
+void ejit_ldi_f(struct ejit_func *s, struct ejit_fpr r0, void *p);
+void ejit_ldi_d(struct ejit_func *s, struct ejit_fpr r0, void *p);
+
+/* from r1 + o to r0 */
+void ejit_ldxi_8(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_ldxi_16(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_ldxi_32(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_ldxi_64(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+
+void ejit_ldxi_uc(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_ldxi_us(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_ldxi_ui(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_ldxi_ul(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+
+void ejit_ldxi_f(struct ejit_func *s, struct ejit_fpr r0, struct ejit_gpr r1, long o);
+void ejit_ldxi_d(struct ejit_func *s, struct ejit_fpr r0, struct ejit_gpr r1, long o);
+
+void ejit_sti_8(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_sti_16(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_sti_32(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_sti_64(struct ejit_func *s, struct ejit_gpr r0, void *p);
+
+void ejit_sti_u8(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_sti_u16(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_sti_u32(struct ejit_func *s, struct ejit_gpr r0, void *p);
+void ejit_sti_u64(struct ejit_func *s, struct ejit_gpr r0, void *p);
+
+void ejit_sti_f(struct ejit_func *s, struct ejit_fpr r0, void *p);
+void ejit_sti_d(struct ejit_func *s, struct ejit_fpr r0, void *p);
+
+/* from r0 to r1 + o */
+void ejit_stxi_8(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_stxi_16(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_stxi_32(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_stxi_64(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+
+void ejit_stxi_u8(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_stxi_u16(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_stxi_u32(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+void ejit_stxi_u64(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, long o);
+
+void ejit_stxi_f(struct ejit_func *s, struct ejit_fpr r0, struct ejit_gpr r1, long o);
+void ejit_stxi_d(struct ejit_func *s, struct ejit_fpr r0, struct ejit_gpr r1, long o);
+
+void ejit_addr(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, struct ejit_gpr r2);
+void ejit_addr_f(struct ejit_func *s, struct ejit_fpr r0, struct ejit_fpr r1, struct ejit_fpr r2);
+
+void ejit_subr(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, struct ejit_gpr r2);
+void ejit_subr_f(struct ejit_func *s, struct ejit_fpr r0, struct ejit_fpr r1, struct ejit_fpr r2);
+
+/** @todo branches, should I do the nifty label trick again? */
+struct ejit_reloc ejit_bltr(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1);
+
+void ejit_patch(struct ejit_func *s, struct ejit_reloc r, struct ejit_label l);
+
+#endif /* EJIT_H */
diff --git a/scripts/gen-deps b/scripts/gen-deps
new file mode 100755
index 0000000..f45707c
--- /dev/null
+++ b/scripts/gen-deps
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+PREFIX=
+COMPILE=COMPILE
+LINT=LINT
+BUILD=build/
+
+while getopts "p:c:b:l:" opt; do
+	case "$opt" in
+		p) PREFIX="$OPTARG"_;;
+		c) COMPILE="$OPTARG";;
+		l) LINT="$OPTARG";;
+		b) BUILD=build/"$OPTARG";;
+		*) echo "unrecognised option -$OPTARG" >&2; exit 1;;
+	esac
+done
+
+shift $((OPTIND - 1))
+
+# create all subdirectories
+mkdir -p $(echo "${@}" | tr ' ' '\n' | sed "s|[^/]*$||;s|^|${BUILD}/|" | uniq)
+
+for s in ${@}
+do
+	obj="${BUILD}/${s%.*}.o"
+	lint="${obj}.l"
+	dep="${obj}.d"
+
+	echo "${PREFIX}OBJS += ${obj}"			>> deps.mk
+	echo "${PREFIX}LINTS += ${lint}"		>> deps.mk
+	echo "${dep}:"					>> deps.mk
+	echo "-include ${dep}"				>> deps.mk
+	echo "${obj}: ${s}"				>> deps.mk
+	echo "	\$(${COMPILE}) -c ${s} -o ${obj}"	>> deps.mk
+	echo "${lint}: ${s}"				>> deps.mk
+	echo "	\$(${LINT}) -c ${s} -o /dev/null"	>> deps.mk
+done
diff --git a/scripts/license b/scripts/license
new file mode 100755
index 0000000..53bd5da
--- /dev/null
+++ b/scripts/license
@@ -0,0 +1,16 @@
+#!/bin/sh
+
+SPDX="/* SPDX-License-Identifier: copyleft-next-0.3.1 */"
+
+for f in "$@"
+do
+	if [ "$(head -1 "$f")" != "${SPDX}" ]
+	then
+		sed -i "1i${SPDX}\n" "$f"
+	fi
+
+	if ! grep 'Copyright' "$f" > /dev/null
+	then
+		echo "Missing copyright info in $f"
+	fi
+done
diff --git a/scripts/makefile b/scripts/makefile
new file mode 100644
index 0000000..484d04f
--- /dev/null
+++ b/scripts/makefile
@@ -0,0 +1,71 @@
+# this could be done better
+RELEASE		?= 0
+OPTFLAGS	!= [ "$(RELEASE)" != "0" ] \
+			&& echo "-O2" \
+			|| echo "-O0"
+
+DEBUG		?= 1
+DEBUGFLAGS	!= [ "$(DEBUG)" != "0" ] \
+			&& echo "-DDEBUG=1" \
+			|| echo "-DNDEBUG=1"
+
+ASSERT		?= 1
+ASSERTFLAGS	!= [ "$(ASSERT)" != "0" ] \
+			&& echo "-DASSERT=1" \
+			|| echo
+
+DEPFLAGS	= -MT $@ -MMD -MP -MF $@.d
+LINTFLAGS	:= -fsyntax-only
+PREPROCESS	:= -E
+
+LLVM		?= 0
+BUILD		:= build
+
+all: ejit.o
+
+# default values, overwrite if/when needed
+CROSS_COMPILE	:=
+
+OBJCOPY		!= [ "$(LLVM)" != "0" ] \
+			&& echo llvm-objcopy \
+			|| echo $(CROSS_COMPILE)objcopy
+
+COMPILER	!= [ "$(LLVM)" != "0" ] \
+			&& echo clang --target="$(CROSS_COMPILE)" \
+			|| echo $(CROSS_COMPILE)gcc
+
+
+OBFLAGS		:= -g
+# interpreter is allowed to have uninitialized values
+WARNFLAGS	:= -Wall -Wextra -Wno-maybe-uninitialized
+
+COMPILE_FLAGS	:= $(CFLAGS) $(WARNFLAGS) $(OPTFLAGS) $(OBFLAGS) $(ASSERTFLAGS) \
+		   $(DEBUGFLAGS)
+
+INCLUDE_FLAGS	:= -I include
+
+COMPILE		= $(COMPILER) \
+		  $(COMPILE_FLAGS) $(DEPFLAGS) $(INCLUDE_FLAGS)
+
+LINT		= $(COMPILER) \
+		  $(COMPILE_FLAGS) $(LINTFLAGS) $(INCLUDE_FLAGS)
+
+UBSAN		?= 0
+UBSAN_FLAGS	!= [ "$(UBSAN)" != "0" ] \
+			&& echo -fsanitize=undefined \
+			|| echo
+
+COMPILE_EJIT	= $(COMPILE) $(EJIT_FLAGS)
+
+-include deps.mk
+
+ejit.o: $(EJIT_OBJS)
+	ld -relocatable $(EJIT_OBJS) -o $@
+
+examples: examples/exec
+examples/exec: examples/main.c ejit.o
+	$(COMPILE_EJIT) examples/main.c ejit.o -o $@
+
+# might lint some common things twice
+.PHONY:
+lint: $(TRISCV_LINTS)
diff --git a/scripts/warn-undocumented b/scripts/warn-undocumented
new file mode 100755
index 0000000..db22249
--- /dev/null
+++ b/scripts/warn-undocumented
@@ -0,0 +1,7 @@
+#!/bin/sh
+# look through all files for either @file or \file
+for file in $@
+do
+	grep -c '[@\]file' "$file" |\
+	awk -F':' "\$1 == 0 {print \"Undocumented file: $file\"}"
+done
diff --git a/src/common.h b/src/common.h
new file mode 100644
index 0000000..21e881b
--- /dev/null
+++ b/src/common.h
@@ -0,0 +1,126 @@
+#ifndef EJIT_COMMON_H
+#define EJIT_COMMON_H
+
+#include <stdbool.h>
+#include "vec.h"
+
+enum ejit_opcode {
+	MOVI,
+	MOVR,
+	MOVR_F,
+
+	LDI8,
+	LDI16,
+	LDI32,
+	LDI64,
+	LDIU8,
+	LDIU16,
+	LDIU32,
+	LDIU64,
+	LDIF,
+	LDID,
+
+	LDXI8,
+	LDXI16,
+	LDXI32,
+	LDXI64,
+	LDXIU8,
+	LDXIU16,
+	LDXIU32,
+	LDXIU64,
+	LDXIF,
+	LDXID,
+
+	STI8,
+	STI16,
+	STI32,
+	STI64,
+	STIU8,
+	STIU16,
+	STIU32,
+	STIU64,
+	STIF,
+	STID,
+
+	STXI8,
+	STXI16,
+	STXI32,
+	STXI64,
+	STXIU8,
+	STXIU16,
+	STXIU32,
+	STXIU64,
+	STXIF,
+	STXID,
+
+	ADDR,
+	ADDR_F,
+	SUBR,
+	SUBR_F,
+
+	BLTR,
+
+	PARAM,
+	PARAM_F,
+
+	ARG,
+	ARG_I,
+	ARG_F,
+	ARG_FI,
+
+	ESCAPEI,
+	ESCAPEI_F,
+
+	CALLI,
+	CALLI_F,
+
+	RET,
+	RET_I,
+	RET_F,
+	RET_FI,
+
+	RETVAL,
+	RETVAL_F,
+
+	START,
+	END,
+
+	OPCODE_COUNT,
+};
+
+struct ejit_insn {
+	union {
+		enum ejit_opcode op;
+		void *addr;
+	};
+
+	size_t r0;
+	size_t r1;
+	union {
+		size_t r2;
+		void *p;
+		long o;
+		double d;
+	};
+};
+
+struct ejit_func {
+	struct vec insns;
+	enum ejit_type rtype;
+
+	size_t gpr;
+	size_t fpr;
+
+	void *arena;
+	size_t size;
+};
+
+
+union interp_ret {
+	long r;
+	double d;
+};
+
+union interp_ret ejit_interp(struct ejit_func *f, size_t argc, struct ejit_arg args[argc], bool run, void ***labels_wb);
+
+#endif /* EJIT_COMMON_H */
diff --git a/src/ejit.c b/src/ejit.c
new file mode 100644
index 0000000..bd5a652
--- /dev/null
+++ b/src/ejit.c
@@ -0,0 +1,190 @@
+#include <assert.h>
+#include <sys/mman.h>
+
+#include <ejit/ejit.h>
+
+#include "common.h"
+
+static void emit_insn_i(struct ejit_func *f, enum ejit_opcode op, size_t r0, size_t r1, long o)
+{
+	struct ejit_insn i = {.op = op, .r0 = r0, .r1 = r1, .o = o};
+	vec_append(&f->insns, &i);
+}
+
+static void emit_insn_r(struct ejit_func *f, enum ejit_opcode op, size_t r0, size_t r1, size_t r2)
+{
+	struct ejit_insn i = {.op = op, .r0 = r0, .r1 = r1, .r2 = r2};
+	vec_append(&f->insns, &i);
+}
+
+static void emit_insn_p(struct ejit_func *f, enum ejit_opcode op, size_t r0, size_t r1, void *p)
+{
+	struct ejit_insn i = {.op = op, .r0 = r0, .r1 = r1, .p = p};
+	vec_append(&f->insns, &i);
+}
+
+static void emit_insn_f(struct ejit_func *f, enum ejit_opcode op, size_t r0, size_t r1, double d)
+{
+	struct ejit_insn i = {.op = op, .r0 = r0, .r1 = r1, .d = d};
+	vec_append(&f->insns, &i);
+}
+
+struct ejit_func *ejit_create_func(enum ejit_type rtype, size_t argc, const struct ejit_operand args[argc])
+{
+	struct ejit_func *f = malloc(sizeof(struct ejit_func));
+	assert(f);
+
+	f->rtype = rtype;
+
+	f->insns = vec_create(sizeof(struct ejit_insn));
+	f->arena = NULL;
+	f->size = 0;
+
+	emit_insn_i(f, START, 0, 0, 0);
+
+	for (size_t i = 0; i < argc; ++i) {
+		switch (args[i].kind) {
+		case EJIT_OPERAND_GPR: emit_insn_i(f, PARAM, args[i].r, 0, i); break;
+		case EJIT_OPERAND_FPR: emit_insn_i(f, PARAM_F, args[i].r, 0, i); break;
+		default: abort();
+		}
+	}
+
+	return f;
+}
+
+void ejit_compile_func(struct ejit_func *f, size_t gpr, size_t fpr)
+{
+	f->gpr = gpr;
+	f->fpr = fpr;
+	/** @todo try to implement JIT */
+	/* otherwise, convert opcodes to address labels */
+
+	void **labels;
+	/* just get labels, don't actually run anything yet */
+	ejit_interp(f, 0, NULL, false, &labels);
+	foreach_vec(ii, f->insns) {
+		struct ejit_insn i = vect_at(struct ejit_insn, f->insns, ii);
+		i.addr = labels[i.op];
+		vect_at(struct ejit_insn, f->insns, ii) = i;
+	}
+}
+
+void ejit_destroy_func(struct ejit_func *f)
+{
+	if (f->arena)
+		munmap(f->arena, f->size);
+
+	vec_destroy(&f->insns);
+	free(f);
+}
+
+struct ejit_label ejit_label(struct ejit_func *f)
+{
+	return (struct ejit_label){.addr = vec_len(&f->insns)};
+}
+
+void ejit_patch(struct ejit_func *f, struct ejit_reloc r, struct ejit_label l)
+{
+	struct ejit_insn i = vect_at(struct ejit_insn, f->insns, r.insn);
+	/** @todo some assert that checks the opcode? */
+	i.o = l.addr;
+	vect_at(struct ejit_insn, f->insns, r.insn) = i;
+}
+
+void ejit_calli(struct ejit_func *s, struct ejit_func *f, size_t argc, const struct ejit_operand args[argc])
+{
+	for (size_t i = 0; i < argc; ++i) {
+		switch (args[i].kind) {
+		case EJIT_OPERAND_GPR: emit_insn_i(s, ARG, args[i].r, args[i].type, 0); break;
+		case EJIT_OPERAND_FPR: emit_insn_i(s, ARG_F, args[i].r, args[i].type, 0); break;
+		case EJIT_OPERAND_IMM: emit_insn_i(s, ARG_I, 0, args[i].type, args[i].r); break;
+		case EJIT_OPERAND_FLT: emit_insn_f(s, ARG_FI, 0, args[i].type, args[i].d); break;
+		default: abort();
+		}
+	}
+
+	emit_insn_p(s, CALLI, 0, 0, f);
+}
+
+void ejit_escapei(struct ejit_func *s, ejit_escape_t f, size_t argc, const struct ejit_operand args[argc])
+{
+	for (size_t i = 0; i < argc; ++i) {
+		switch (args[i].kind) {
+		case EJIT_OPERAND_GPR: emit_insn_i(s, ARG, args[i].r, 0, 0); break;
+		case EJIT_OPERAND_FPR: emit_insn_i(s, ARG_F, args[i].r, 0, 0); break;
+		case EJIT_OPERAND_IMM: emit_insn_i(s, ARG_I, 0, 0, args[i].r); break;
+		case EJIT_OPERAND_FLT: emit_insn_f(s, ARG_FI, 0, 0, args[i].d); break;
+		default: abort();
+		}
+	}
+
+	emit_insn_p(s, ESCAPEI, 0, 0, f);
+}
+
+void ejit_escapei_f(struct ejit_func *s, ejit_escape_f_t f, size_t argc, const struct ejit_operand args[argc])
+{
+	for (size_t i = 0; i < argc; ++i) {
+		switch (args[i].kind) {
+		case EJIT_OPERAND_GPR: emit_insn_i(s, ARG, args[i].r, 0, 0); break;
+		case EJIT_OPERAND_FPR: emit_insn_i(s, ARG_F, args[i].r, 0, 0); break;
+		case EJIT_OPERAND_IMM: emit_insn_i(s, ARG_I, 0, 0, args[i].r); break;
+		case EJIT_OPERAND_FLT: emit_insn_f(s, ARG_FI, 0, 0, args[i].d); break;
+		default: abort();
+		}
+	}
+
+	emit_insn_p(s, ESCAPEI_F, 0, 0, f);
+}
+
+void ejit_ret(struct ejit_func *s, struct ejit_gpr r0)
+{
+	emit_insn_r(s, RET, r0.r, 0, 0);
+}
+
+void ejit_ret_f(struct ejit_func *s, struct ejit_fpr r0)
+{
+	emit_insn_r(s, RET_F, r0.f, 0, 0);
+}
+
+void ejit_ret_i(struct ejit_func *s, long i)
+{
+	emit_insn_i(s, RET_I, 0, 0, i);
+}
+
+void ejit_ret_fi(struct ejit_func *s, double f)
+{
+	emit_insn_f(s, RET_FI, 0, 0, f);
+}
+
+void ejit_addr(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, struct ejit_gpr r2)
+{
+	emit_insn_r(s, ADDR, r0.r, r1.r, r2.r);
+}
+
+void ejit_addr_f(struct ejit_func *s, struct ejit_fpr r0, struct ejit_fpr r1, struct ejit_fpr r2)
+{
+	emit_insn_r(s, ADDR_F, r0.f, r1.f, r2.f);
+}
+
+void ejit_subr(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1, struct ejit_gpr r2)
+{
+	emit_insn_r(s, SUBR, r0.r, r1.r, r2.r);
+}
+
+void ejit_subr_f(struct ejit_func *s, struct ejit_fpr r0, struct ejit_fpr r1, struct ejit_fpr r2)
+{
+	emit_insn_r(s, SUBR_F, r0.f, r1.f, r2.f);
+}
+
+void ejit_movi(struct ejit_func *s, struct ejit_gpr r0, long o)
+{
+	emit_insn_i(s, MOVI, r0.r, 0, o);
+}
+
+struct ejit_reloc ejit_bltr(struct ejit_func *s, struct ejit_gpr r0, struct ejit_gpr r1)
+{
+	struct ejit_label label = ejit_label(s);
+	emit_insn_i(s, BLTR, r0.r, r1.r, 0);
+	return (struct ejit_reloc){.insn = label.addr};
+}
diff --git a/src/interp.c b/src/interp.c
new file mode 100644
index 0000000..4678aa1
--- /dev/null
+++ b/src/interp.c
@@ -0,0 +1,190 @@
+#include <ejit/ejit.h>
+
+#include "common.h"
+
+
+union interp_ret ejit_interp(struct ejit_func *f, size_t argc, struct ejit_arg args[argc], bool run, void ***labels_wb)
+{
+	static void *labels[OPCODE_COUNT] = {
+		[MOVI] = &&movi,
+		[MOVR] = &&movr,
+		[MOVR_F] = &&movr_f,
+
+		[ADDR] = &&addr,
+		[ADDR_F] = &&addr_f,
+		[SUBR] = &&subr,
+		[SUBR_F] = &&subr_f,
+
+		[BLTR] = &&bltr,
+
+		[RET] = &&ret,
+		[RET_I] = &&ret_i,
+		[RET_F] = &&ret_f,
+		[RET_FI] = &&ret_fi,
+
+		[ARG] = &&arg,
+		[ARG_I] = &&arg_i,
+		[ARG_F] = &&arg_f,
+		[ARG_FI] = &&arg_fi,
+
+		[PARAM] = &&param,
+		[PARAM_F] = &&param_f,
+
+		[CALLI] = &&calli,
+		[CALLI_F] = &&calli_f,
+
+		[START] = &&start,
+		[END] = &&end,
+	};
+
+	if (!run) {
+		*labels_wb = labels;
+		return (union interp_ret){.r = 0};
+	}
+
+	/** @todo this can be optimized by for example using a common buffer
+	 * 'stack' */
+	long *gpr = malloc(f->gpr * sizeof(long));
+	long *fpr = malloc(f->fpr * sizeof(long));
+	struct vec call_args = vec_create(sizeof(struct ejit_arg));
+	struct ejit_insn *insns = f->insns.buf;
+
+	struct ejit_insn i;
+	long retval = 0; double retval_f = 0.;
+	size_t pc = 0;
+
+#define DO(x) x: { i = insns[pc];
+#define JUMP(a) goto *insns[pc = a].addr;
+#define DISPATCH() } goto *insns[++pc].addr;
+
+	DO(start);
+	DISPATCH();
+
+	DO(end);
+	goto out_int;
+	DISPATCH();
+
+	DO(movi);
+	gpr[i.r0] = i.o;
+	DISPATCH();
+
+	DO(movr);
+	gpr[i.r0] = gpr[i.r1];
+	DISPATCH();
+
+	DO(movr_f);
+	fpr[i.r0] = fpr[i.r1];
+	DISPATCH();
+
+	DO(addr);
+	gpr[i.r0] = gpr[i.r1] + gpr[i.r2];
+	DISPATCH();
+
+	DO(addr_f);
+	fpr[i.r0] = fpr[i.r1] + fpr[i.r2];
+	DISPATCH();
+
+	DO(subr);
+	gpr[i.r0] = gpr[i.r1] - gpr[i.r2];
+	DISPATCH();
+
+	DO(subr_f);
+	fpr[i.r0] = fpr[i.r1] - fpr[i.r2];
+	DISPATCH();
+
+	DO(bltr);
+	if (gpr[i.r0] < gpr[i.r1])
+		JUMP(i.o);
+
+	DISPATCH();
+
+	DO(param);
+	gpr[i.r0] = args[i.o].l;
+	DISPATCH();
+
+	DO(param_f);
+	fpr[i.r0] = args[i.o].d;
+	DISPATCH();
+
+	DO(arg);
+	struct ejit_arg a = ejit_build_arg(i.r1, gpr[i.r0]);
+	vec_append(&call_args, &a);
+	DISPATCH();
+
+	DO(arg_i);
+	struct ejit_arg a = ejit_build_arg(i.r1, i.o);
+	vec_append(&call_args, &a);
+	DISPATCH();
+
+	DO(arg_f);
+	struct ejit_arg a = ejit_build_arg_f(i.r1, fpr[i.r0]);
+	vec_append(&call_args, &a);
+	DISPATCH();
+
+	DO(arg_fi);
+	struct ejit_arg a = ejit_build_arg_f(i.r1, i.d);
+	vec_append(&call_args, &a);
+	DISPATCH();
+
+	DO(calli);
+	struct ejit_func *f = i.p;
+	retval = ejit_run_func(f, vec_len(&call_args), call_args.buf);
+	vec_reset(&call_args);
+	DISPATCH();
+
+	DO(calli_f);
+	struct ejit_func *f = i.p;
+	retval_f = ejit_run_func_f(f, vec_len(&call_args), call_args.buf);
+	vec_reset(&call_args);
+	DISPATCH();
+
+	/* dispatch is technically unnecessary for returns, but keep it for
+	 * symmetry */
+	DO(ret);
+	retval = gpr[i.r0];
+	goto out_int;
+	DISPATCH();
+
+	DO(ret_i);
+	retval = i.o;
+	goto out_int;
+	DISPATCH();
+
+	DO(ret_f);
+	retval_f = fpr[i.r0];
+	goto out_float;
+	DISPATCH();
+
+	DO(ret_fi);
+	retval_f = i.d;
+	goto out_float;
+	DISPATCH();
+
+#undef DISPATCH
+#undef JUMP
+#undef DO
+
+out_int:
+	vec_destroy(&call_args);
+	free(gpr);
+	free(fpr);
+	return (union interp_ret){.r = retval};
+
+out_float:
+	vec_destroy(&call_args);
+	free(gpr);
+	free(fpr);
+	return (union interp_ret){.d = retval_f};
+}
+
+long ejit_run_func(struct ejit_func *f, size_t argc, struct ejit_arg args[argc])
+{
+	assert(f->rtype == EJIT_VOID || ejit_int_type(f->rtype));
+	return ejit_interp(f, argc, args, true, NULL).r;
+}
+
+double ejit_run_func_f(struct ejit_func *f, size_t argc, struct ejit_arg args[argc])
+{
+	assert(ejit_float_type(f->rtype));
+	return ejit_interp(f, argc, args, true, NULL).d;
+}
diff --git a/src/source.mk b/src/source.mk
new file mode 100644
index 0000000..907befa
--- /dev/null
+++ b/src/source.mk
@@ -0,0 +1,2 @@
+LOCAL_SOURCES	!= echo src/*.c
+EJIT_SOURCES	:= $(EJIT_SOURCES) $(LOCAL_SOURCES)
diff --git a/src/vec.h b/src/vec.h
new file mode 100644
index 0000000..7a1d5cb
--- /dev/null
+++ b/src/vec.h
@@ -0,0 +1,95 @@
+#ifndef VEC_H
+#define VEC_H
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+struct vec {
+	size_t n;
+	size_t s;
+	size_t ns;
+	void *buf;
+};
+
+#define foreach_vec(iter, v) \
+	for (size_t iter = 0; iter < vec_len(&v); ++iter)
+
+#define vect_at(type, v, i) \
+	*(type *)vec_at(&v, i)
+
+#define vect_append(type, v, e) \
+	vec_append(&v, (type *)(e))
+
+#define vect_back(type, v) \
+	*(type *)vec_back(&v)
+
+#define vect_pop(type, v) \
+	*(type *)vec_pop(&v)
+
+#define vec_uninit(v) \
+	(v.buf == NULL)
+
+static inline struct vec vec_create(size_t ns)
+{
+	return (struct vec) {
+		       .n = 0,
+		       .s = 1,
+		       .ns = ns,
+		       .buf = malloc(ns),
+	};
+}
+
+static inline size_t vec_len(struct vec *v)
+{
+	return v->n;
+}
+
+static inline void *vec_at(struct vec *v, size_t i)
+{
+	assert(i < v->n && "out of vector bounds");
+	return v->buf + i * v->ns;
+}
+
+static inline void *vec_back(struct vec *v)
+{
+	assert(v->n);
+	return v->buf + (v->n - 1) * v->ns;
+}
+
+static inline void *vec_pop(struct vec *v)
+{
+	assert(v->n && "attempting to pop empty vector");
+	v->n--;
+	return v->buf + v->n * v->ns;
+}
+
+static inline void vec_append(struct vec *v, void *n)
+{
+	v->n++;
+	if (v->n >= v->s) {
+		v->s *= 2;
+		v->buf = realloc(v->buf, v->s * v->ns);
+	}
+
+	void *p = vec_at(v, v->n - 1);
+	memcpy(p, n, v->ns);
+}
+
+static inline void vec_reset(struct vec *v)
+{
+	v->n = 0;
+}
+
+static inline void vec_destroy(struct vec *v) {
+	free(v->buf);
+}
+
+typedef int (*vec_comp_t)(void *a, void *b);
+static inline void vec_sort(struct vec *v, vec_comp_t comp)
+{
+	qsort(v->buf, v->n, v->ns, (__compar_fn_t)comp);
+}
+
+#endif /* VEC_H */