usr: Add initial "oasm" assembler work

Signed-off-by: Ian Moffett <ian@osmora.org>

8 files changed, 699 insertions, 0 deletions

diff --git a/usr.bin/oasm/Makefile b/usr.bin/oasm/Makefile
new file mode 100644
index 0000000..a83aaab
--- /dev/null
+++ b/usr.bin/oasm/Makefile
@@ -0,0 +1,7 @@
+include user.mk
+
+CFILES = $(shell find . -name "*.c")
+CFLAGS = -Iinclude/
+
+$(ROOT)/base/usr/bin/oasm:
+	gcc $(CFILES) -o $@ $(INTERNAL_CFLAGS) $(CFLAGS)
diff --git a/usr.bin/oasm/include/oasm/lex.h b/usr.bin/oasm/include/oasm/lex.h
new file mode 100644
index 0000000..6688348
--- /dev/null
+++ b/usr.bin/oasm/include/oasm/lex.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _OASM_LEX_H_
+#define _OASM_LEX_H_
+
+#include <stdint.h>
+#include <oasm/state.h>
+
+#define __XN_REGS   \
+    TT_X0,          \
+    TT_X1,          \
+    TT_X2,          \
+    TT_X3,          \
+    TT_X4,          \
+    TT_X5,          \
+    TT_X6,          \
+    TT_X7,          \
+    TT_X8,          \
+    TT_X9,          \
+    TT_X10,         \
+    TT_X11,         \
+    TT_X12,         \
+    TT_X13,         \
+    TT_X14,         \
+    TT_X15
+
+#define __FN_REGS   \
+    TT_F0,          \
+    TT_F1,          \
+    TT_F2,          \
+    TT_F3,          \
+    TT_F4,          \
+    TT_F5,          \
+    TT_F6,          \
+    TT_F7
+
+#define __DN_REGS   \
+    TT_D0,          \
+    TT_D1,          \
+    TT_D2,          \
+    TT_D3,          \
+    TT_D4,          \
+    TT_D5,          \
+    TT_D6,          \
+    TT_D7
+
+#define __VN_REGS   \
+    TT_V0,          \
+    TT_V1,          \
+    TT_V2,          \
+    TT_V3,          \
+    TT_V4,          \
+    TT_V5,          \
+    TT_V6,          \
+    TT_V7
+
+/*
+ * Token type definitions
+ */
+typedef enum {
+    TT_UNKNOWN,     /* Unknown token */
+
+    /* Arithmetic instructions */
+    TT_ADD,         /* 'add' */
+    TT_SUB,         /* 'sub' */
+    TT_MUL,         /* 'mul' */
+    TT_DIV,         /* 'div' */
+
+    /* Register ops */
+    TT_MOV,
+    TT_INC,
+    TT_DEC,
+
+    /* Register sets */
+    __XN_REGS,
+    __FN_REGS,
+    __DN_REGS,
+    __VN_REGS,
+
+    /* Symbols */
+    TT_COMMA,       /* ',' */
+} tt_t;
+
+struct oasm_token {
+    tt_t type;
+    char *raw;
+};
+
+int lex_tok(struct oasm_state *state, struct oasm_token *ttp);
+
+#endif  /* !_OASM_LEX_H_ */
diff --git a/usr.bin/oasm/include/oasm/log.h b/usr.bin/oasm/include/oasm/log.h
new file mode 100644
index 0000000..330c273
--- /dev/null
+++ b/usr.bin/oasm/include/oasm/log.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _OASM_LOG_H_
+#define _OASM_LOG_H_
+
+#include <sys/types.h>
+#include <sys/cdefs.h>
+#include <stdio.h>
+
+#define ERROR_COLOR "\033[31;40m"
+#define WARN_COLOR  "\033[35;40m"
+
+void __oasm_debug(const char *fmt, ...);
+void __oasm_err(const char *fmt, ...);
+void __oasm_warn(const char *fmt, ...);
+
+#define oasm_debug(...) __oasm_debug(__VA_ARGS__)
+#define oasm_err(...) __oasm_err(__VA_ARGS__)
+#define oasm_warn(...) __oasm_warn(__VA_ARGS__)
+
+#endif  /* !_OASM_LOG_H_ */
diff --git a/usr.bin/oasm/include/oasm/parse.h b/usr.bin/oasm/include/oasm/parse.h
new file mode 100644
index 0000000..04962e7
--- /dev/null
+++ b/usr.bin/oasm/include/oasm/parse.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _OASM_PARSE_H_
+#define _OASM_PARSE_H_
+
+#include <oasm/state.h>
+
+void parse_enter(struct oasm_state *state);
+
+#endif /* !_OASM_PARSE_H_ */
diff --git a/usr.bin/oasm/include/oasm/state.h b/usr.bin/oasm/include/oasm/state.h
new file mode 100644
index 0000000..c21d877
--- /dev/null
+++ b/usr.bin/oasm/include/oasm/state.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _OASM_STATE_H_
+#define _OASM_STATE_H_
+
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+struct oasm_state {
+    int in_fd;
+};
+
+#endif  /* !_OASM_STATE_H_ */
diff --git a/usr.bin/oasm/lex.c b/usr.bin/oasm/lex.c
new file mode 100644
index 0000000..a61c62a
--- /dev/null
+++ b/usr.bin/oasm/lex.c
@@ -0,0 +1,272 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/errno.h>
+#include <string.h>
+#include <oasm/state.h>
+#include <oasm/lex.h>
+#include <oasm/log.h>
+
+#define is_num(c) ((c) >= '0' && (c) <= '9')
+
+static char putback = '\0';
+
+/* Instruction mnemonic strings */
+#define S_IMN_MOV  "mov"
+#define S_IMN_ADD  "add"
+#define S_IMN_SUB  "sub"
+#define S_IMN_DIV  "div"
+#define S_IMN_INC  "inc"
+#define S_IMN_DEC  "dec"
+
+/*
+ * Returns 0 if a char is counted as a
+ * skippable token. Otherwise, -1
+ */
+static inline int
+lex_skippable(char c)
+{
+    switch (c) {
+    case ' ':
+    case '\f':
+    case '\t':
+    case '\r':
+    case '\n':
+        return 0;
+    }
+
+    return -1;
+}
+
+/*
+ * Put back a token to grab later
+ *
+ * @c: Character to put back
+ */
+static inline char
+lex_putback(char c)
+{
+    putback = c;
+    return c;
+}
+
+/*
+ * Grab a character from the input file
+ * descriptor.
+ */
+static char
+lex_cin(struct oasm_state *state)
+{
+    char retval;
+
+    if (putback != '\0') {
+        retval = putback;
+        putback = '\0';
+        return retval;
+    }
+
+    if (read(state->in_fd, &retval, 1) <= 0) {
+        return '\0';
+    }
+    return retval;
+}
+
+/*
+ * Nom an operation, directive or any kind
+ * of raw string (unquoted/builtin) and return
+ * memory allocated by strdup() pointing to the
+ * string.
+ *
+ * @state: OASM state pointer
+ * @res: Resulting string
+ *
+ * Returns 0 on success. Greater than zero
+ * value of the last character if a comma or
+ * space was not buffered.
+ */
+static int
+lex_nomstr(struct oasm_state *state, char **res)
+{
+    char buf[256];
+    int retval = 0, n = 0;
+    int tmp;
+
+    memset(buf, 0, sizeof(buf));
+
+    /*
+     * We are filling the buffer containing
+     * the operation or directive.
+     *
+     * Keep going until we hit a space or comman (^)
+     * Examples of such strings (everything in '[]'):
+     *
+     * [mov] [x0], [#1]
+     *      ^    ^
+     */
+    while ((tmp = lex_cin(state)) != 0) {
+        if (tmp == ' ' || tmp == ',') {
+            retval = tmp;
+            break;
+        }
+        if (tmp == '\n') {
+            retval = tmp;
+            break;
+
+        }
+
+        buf[n++] = tmp;
+    }
+
+    *res = strdup(buf);
+    return retval;
+}
+
+static tt_t
+token_arith(char *p)
+{
+    if (strcmp(p, S_IMN_MOV) == 0) {
+        return TT_MOV;
+    } else if (strcmp(p, S_IMN_INC) == 0) {
+        return TT_INC;
+    } else if (strcmp(p, S_IMN_DEC) == 0) {
+        return TT_DEC;
+    } else if (strcmp(p, S_IMN_ADD) == 0) {
+        return TT_ADD;
+    } else if (strcmp(p, S_IMN_SUB) == 0) {
+        return TT_SUB;
+    } else if (strcmp(p, S_IMN_DIV) == 0) {
+        return TT_DIV;
+    }
+
+    return TT_UNKNOWN;
+}
+
+static tt_t
+token_xreg(char *p)
+{
+    int num;
+
+    if (p[0] != 'x') {
+        return TT_UNKNOWN;
+    }
+
+    if (!is_num(p[1])) {
+        return TT_UNKNOWN;
+    }
+
+    num = atoi(&p[1]);
+    switch (num) {
+        case 0: return TT_X0;
+        case 1: return TT_X1;
+        case 2: return TT_X2;
+        case 3: return TT_X3;
+        case 4: return TT_X4;
+        case 5: return TT_X5;
+        case 6: return TT_X6;
+        case 7: return TT_X7;
+        case 8: return TT_X8;
+        case 9: return TT_X9;
+        case 10: return TT_X10;
+        case 11: return TT_X11;
+        case 12: return TT_X12;
+        case 13: return TT_X13;
+        case 14: return TT_X14;
+        case 15: return TT_X15;
+    }
+
+    return TT_UNKNOWN;
+}
+
+static tt_t
+token_reg(char *p)
+{
+    tt_t tok;
+
+    if ((tok = token_xreg(p)) != TT_UNKNOWN) {
+        return tok;
+    }
+
+    return TT_UNKNOWN;
+}
+
+int
+lex_tok(struct oasm_state *state, struct oasm_token *ttp)
+{
+    char *p;
+    char c = ' ';
+    int tmp;
+    tt_t tok;
+
+    if (state == NULL || ttp == NULL) {
+        return -EINVAL;
+    }
+
+    /*
+     * Grab characters. If they are skippable,
+     * don't use them.
+     */
+    while (lex_skippable(c) == 0) {
+        if ((c = lex_cin(state)) == 0) {
+            return -1;
+        }
+    }
+
+    switch (c) {
+    case '\n':
+        return 0;
+    case '\0':
+        return -1;
+    case ',':
+        return TT_COMMA;
+    default:
+        ttp->type = TT_UNKNOWN;
+        ttp->raw = NULL;
+
+        lex_putback(c);
+        lex_nomstr(state, &p);
+
+        /* Arithmetic operation? */
+        if ((tok = token_arith(p)) != TT_UNKNOWN) {
+            ttp->type = tok;
+            ttp->raw = p;
+            return 0;
+        }
+
+        /* Register? */
+        if ((tok = token_reg(p)) != TT_UNKNOWN) {
+            ttp->type = tok;
+            ttp->raw = p;
+            return 0;
+        }
+        oasm_err("bad token %s\n", p);
+        return -1;
+    }
+
+    return 0;
+}
diff --git a/usr.bin/oasm/oasm.c b/usr.bin/oasm/oasm.c
new file mode 100644
index 0000000..670a5f4
--- /dev/null
+++ b/usr.bin/oasm/oasm.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <oasm/state.h>
+#include <oasm/parse.h>
+#define OASM_DBG
+#include <oasm/log.h>
+
+static struct oasm_state state;
+
+static void
+oasm_start(struct oasm_state *state)
+{
+    parse_enter(state);
+}
+
+int
+main(int argc, char **argv)
+{
+    if (argc < 2) {
+        printf("oasm: usage: oasm <file> <output>\n");
+        return -1;
+    }
+
+    state.in_fd = open(argv[1], O_RDONLY);
+    if (state.in_fd < 0) {
+        printf("could not open \"%s\"\n", argv[1]);
+        return -1;
+    }
+
+    oasm_start(&state);
+    close(state.in_fd);
+    return 0;
+}
diff --git a/usr.bin/oasm/parse.c b/usr.bin/oasm/parse.c
new file mode 100644
index 0000000..45c697a
--- /dev/null
+++ b/usr.bin/oasm/parse.c
@@ -0,0 +1,113 @@
+/* Copyright (c) 2023-2025 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <oasm/state.h>
+#include <oasm/lex.h>
+#include <oasm/parse.h>
+#include <oasm/log.h>
+
+static const char *tokstr[] = {
+    [ TT_UNKNOWN] = "bad",
+    [ TT_ADD ] = "add",
+    [ TT_SUB ] = "sub",
+    [ TT_MUL ] = "mul",
+    [ TT_DIV ] = "div",
+    [ TT_COMMA ] = ",",
+    [ TT_INC ] = "inc",
+    [ TT_DEC ] = "dec",
+    [ TT_MOV ] = "mov",
+
+    /* X<n> registers */
+    [ TT_X0 ]  = "x0",
+    [ TT_X1 ]  = "x1",
+    [ TT_X2 ]  = "x2",
+    [ TT_X3 ]  = "x3",
+    [ TT_X4 ]  = "x4",
+    [ TT_X5 ]  = "x5",
+    [ TT_X6 ]  = "x6",
+    [ TT_X7  ] = "x7",
+    [ TT_X8 ]  = "x8",
+    [ TT_X9 ]  = "x9",
+    [ TT_X10 ] = "x10",
+    [ TT_X11 ] = "x11",
+    [ TT_X12 ] = "x12",
+    [ TT_X13 ] = "x13",
+    [ TT_X14 ] = "x14",
+    [ TT_X15 ] = "x15",
+
+    /* V<n> registers */
+    [ TT_F0 ]  = "v0",
+    [ TT_F1 ]  = "v1",
+    [ TT_F2 ]  = "v2",
+    [ TT_F3 ]  = "v3",
+    [ TT_F4 ]  = "v4",
+    [ TT_F5 ]  = "v5",
+    [ TT_F6 ]  = "v6",
+    [ TT_F7 ]  = "v7",
+
+    /* D<n> registers */
+    [ TT_D0 ]  = "d0",
+    [ TT_D1 ]  = "d1",
+    [ TT_D2 ]  = "d2",
+    [ TT_D3 ]  = "d3",
+    [ TT_D4 ]  = "d4",
+    [ TT_D5 ]  = "d5",
+    [ TT_D6 ]  = "d6",
+    [ TT_D7 ]  = "d7",
+
+    /* V<n> registers */
+    [ TT_V0 ]  = "v0",
+    [ TT_V1 ]  = "v1",
+    [ TT_V2 ]  = "v2",
+    [ TT_V3 ]  = "v3",
+    [ TT_V4 ]  = "v4",
+    [ TT_V5 ]  = "v5",
+    [ TT_V6 ]  = "v6",
+    [ TT_V7 ]  = "v7",
+};
+
+void
+parse_enter(struct oasm_state *state)
+{
+    struct oasm_token tok;
+    int error = 0;
+
+    for (;;) {
+        error = lex_tok(state, &tok);
+        if (error < 0) {
+            break;
+        }
+
+        if (tok.raw != NULL) {
+            free(tok.raw);
+        }
+    }
+}