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Diffstat (limited to 'usr.bin/oasm/lex.c')
| -rw-r--r-- | usr.bin/oasm/lex.c | 294 |
1 files changed, 294 insertions, 0 deletions
diff --git a/usr.bin/oasm/lex.c b/usr.bin/oasm/lex.c new file mode 100644 index 0000000..afbe21d --- /dev/null +++ b/usr.bin/oasm/lex.c @@ -0,0 +1,294 @@ +/* + * 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(struct oasm_state *state, char c) +{ + switch (c) { + case ' ': return 0; + case '\f': return 0; + case '\t': return 0; + case '\r': return 0; + case '\n': + ++state->line; + 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') { + ++state->line; + 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_operand(char *p) +{ + /* Is this a numeric constant? */ + if (p[0] == '#') { + return TT_IMM; + } + + 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(state, c) == 0) { + if ((c = lex_cin(state)) == 0) { + return -1; + } + } + + switch (c) { + case '\n': + ++state->line; + 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->is_reg = 1; + ttp->type = tok; + ttp->raw = p; + return 0; + } + + /* Immediate operand? */ + if ((tok = token_operand(p)) != TT_UNKNOWN) { + ttp->type = tok; + ttp->raw = p; + return 0; + } + oasm_err("bad token \"%s\"\n", p); + return -1; + } + + return 0; +} |