Add step 1 of assembler
diff --git a/as/as.c b/as/as.c
new file mode 100644
index 0000000..61ad6bd
--- /dev/null
+++ b/as/as.c
@@ -0,0 +1,439 @@
+#include "as.h"
+#include "../cpu.h"
+#include "../instructions.h"
+#include "../mnemonics.h"
+
+#include <collect/map.h>
+#include <collect/vector.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdbool.h>
+
+enum
+{
+ ARG_16, /* Absolute 16 bit argument */
+ ARG_8, /* Absolute 8 bit argument */
+ ARG_8REL, /* Relative 8 bit argument */
+ ARG_REL, /* Relative label */
+ ARG_ABS, /* Absolute label */
+ ARG_IMP, /* Implied argument */
+};
+
+typedef struct
+{
+ uint8_t opcode;
+ uint8_t arg_type;
+ union
+ {
+ char label[32];
+ uint16_t long_arg;
+ uint8_t byte_arg;
+ int8_t rel_arg;
+ };
+} inst_t;
+
+void print_inst(inst_t *arg)
+{
+ char *arg_types =
+ "16 8 8RELREL ABS IMP ";
+
+ printf("\033[33mInst: %.4s $%x ", arg_types + arg->arg_type * 4, arg->opcode);
+
+ switch (arg->arg_type)
+ {
+ case ARG_16:
+ printf("%x", arg->long_arg);
+ break;
+ case ARG_8:
+ printf("%x", arg->byte_arg);
+ break;
+ case ARG_8REL:
+ printf("%d", arg->rel_arg);
+ break;
+ case ARG_REL:
+ case ARG_ABS:
+ printf("%s", arg->label);
+ break;
+ }
+
+ printf("\033[0m\n");
+}
+
+bool is_ident(char c)
+{
+ return c && (isalpha(c) || isdigit(c));
+}
+
+uint32_t skip_ws(char **code)
+{
+ uint32_t len = 0;
+
+ for (; isspace(**code); (*code)++, len++)
+ {}
+
+ return len;
+}
+
+uint32_t skip_to_eol(char **code)
+{
+ uint32_t len = 0;
+
+ for (; **code && **code != '\n'; (*code)++, len++)
+ {}
+
+ if (**code)
+ (*code)++;
+
+ return len;
+}
+
+char *parse_label_name(char **code)
+{
+ char *start = *code;
+ for (; is_ident(**code); (*code)++)
+ {}
+
+ if (start == *code)
+ return false;
+
+ **code = 0;
+ return start;
+}
+
+char *parse_label(char **code)
+{
+ char *start = *code;
+
+ for (; is_ident(**code); (*code)++)
+ {}
+
+ skip_ws(code);
+
+ if (**code == ':')
+ {
+ **code = 0;
+ (*code)++;
+ return start;
+ }
+
+ *code = start;
+
+ return NULL;
+}
+
+char *parse_inst(char **code)
+{
+ char *start = *code;
+
+ for (; isalpha(**code); (*code)++)
+ {}
+
+ **code = 0;
+
+ if (start == *code)
+ return NULL;
+
+ (*code)++;
+ return start;
+}
+
+bool is_eol(char c)
+{
+ return c == ';' ||
+ c == '\n' ||
+ c == '\r' ||
+ c == '\0';
+}
+
+bool skip(char **code, const char *p)
+{
+ for (; *p && *p == **code; p++, (*code)++)
+ {}
+
+ if (!*p)
+ return true;
+ return false;
+}
+
+bool parse_num(char **code, uint64_t *num)
+{
+ char *start = *code;
+ int base = 10;
+ if (**code == '$')
+ {
+ base = 16;
+ (*code)++;
+ }
+
+ skip_ws(code);
+
+ char *endptr = *code;
+ int64_t val = strtol(*code, &endptr, base);
+
+ if (*code == endptr)
+ {
+ *code = start;
+ return false;
+ }
+ *num = val;
+ *code = endptr;
+ return true;
+}
+
+bool parse_num_max(char **code, uint64_t *num, uint64_t max)
+{
+ uint64_t n;
+ if (parse_num(code, &n))
+ {
+ if (n > max)
+ return false;
+
+ *num = n;
+ return true;
+ }
+ else return false;
+}
+
+bool parse_u8(char **code, uint8_t *num)
+{
+ uint64_t n;
+ if (!parse_num_max(code, &n, 0xFF))
+ return false;
+
+ *num = n & 0xFF;
+ return true;
+}
+
+bool parse_u16(char **code, uint16_t *num)
+{
+ uint64_t n;
+ if (!parse_num_max(code, &n, 0xFFFF))
+ return false;
+
+ *num = n & 0xFFFF;
+ return true;
+}
+
+bool ws_end(char **code)
+{
+ skip_ws(code);
+ return is_eol(**code);
+}
+
+bool parse_arg(char *code, int am, inst_t *inst)
+{
+ skip_ws(&code);
+
+ uint16_t num;
+ uint8_t num8;
+ char *lbl;
+
+ switch (am)
+ {
+ case AM_ACC:
+ case AM_IMP:
+ printf("Trying AM_IMP on '%.8s'\n", code);
+ skip_ws(&code);
+ if (is_eol(*code))
+ {
+ inst->arg_type = ARG_IMP;
+ return ws_end(&code);
+ }
+ break;
+
+ case AM_IMM:
+ printf("Trying AM_IMM on '%.8s'\n", code);
+ if (!skip(&code, "#"))
+ return false;
+ skip_ws(&code);
+ case AM_ZP:
+ if (parse_u8(&code, &num8))
+ {
+ inst->arg_type = ARG_8;
+ inst->byte_arg = num8;
+
+ return ws_end(&code);
+ }
+ break;
+
+ case AM_ABS:
+ if (parse_u16(&code, &num))
+ {
+ inst->arg_type = ARG_16;
+ inst->long_arg = num;
+ return true;
+ }
+ else if ((lbl = parse_label_name(&code)))
+ {
+ inst->arg_type = ARG_ABS;
+ strncpy(inst->label, lbl, 32);
+ return true;
+ }
+ break;
+
+ case AM_REL:
+ if (parse_u8(&code, &num8))
+ {
+ inst->arg_type = ARG_8REL;
+ inst->rel_arg = num;
+ return ws_end(&code);
+ }
+ else if ((lbl = parse_label_name(&code)))
+ {
+ inst->arg_type = ARG_REL;
+ strncpy(inst->label, lbl, 32);
+ return ws_end(&code);
+ }
+ break;
+
+ case AM_IND:
+ if (!skip(&code,"("))
+ return false;
+
+ if (!parse_u16(&code, &num))
+ return false;
+
+ if (!skip(&code, ")"))
+ return false;
+
+ inst->arg_type = ARG_16;
+ inst->long_arg = num;
+ return true;
+
+ case AM_AX:
+ case AM_ZPX:
+ case AM_AY:
+ case AM_ZPY:
+ if (am == AM_AX || am == AM_AY)
+ {
+ if (!parse_u16(&code, &num))
+ return false;
+ inst->arg_type = ARG_16;
+ inst->long_arg = num;
+ }
+ else
+ {
+ if (!parse_u8(&code, &num8))
+ return false;
+ inst->arg_type = ARG_8;
+ inst->byte_arg = num8;
+ }
+ if (!skip(&code, ","))
+ return false;
+
+ skip_ws(&code);
+
+ if (tolower(*code) != (am == AM_AY || am == AM_ZPY ? 'y' : 'x'))
+ return false;
+
+ return ws_end(&code);
+
+ case AM_ZIX:
+ if (!skip(&code, "("))
+ break;
+ skip_ws(&code);
+ if (!parse_u8(&code, &num8))
+ break;
+ skip_ws(&code);
+ if (!skip(&code, ","))
+ break;
+ skip_ws(&code);
+ if (tolower(*code) != 'x')
+ return false;
+ skip_ws(&code);
+
+ if (!skip(&code, ")"))
+ break;
+
+ inst->arg_type = ARG_8;
+ inst->byte_arg = num8;
+ return ws_end(&code);
+
+ case AM_ZIY:
+ if (!skip(&code, "("))
+ break;
+ skip_ws(&code);
+ if (!parse_u8(&code, &num8))
+ break;
+ skip_ws(&code);
+ if (!skip(&code, ")"))
+ break;
+ skip_ws(&code);
+ if (!skip(&code, ","))
+ break;
+ skip_ws(&code);
+ if (tolower(*code) != 'x')
+ break;
+
+ inst->arg_type = ARG_8;
+ inst->byte_arg = num8;
+ return ws_end(&code);
+ }
+ return false;
+}
+
+uint32_t assemble(char *code, FILE *out)
+{
+ uintptr_t num_insts = 0;
+ uint32_t line_no = 1;
+ map *labels = new_map();
+ vector *insts = new_vector();
+ char *line;
+
+ printf("Assembling File\n");
+ printf("%s\n", code);
+
+ line = strtok(code, "\r\n");
+
+ while (line)
+ {
+ skip_ws(&line);
+
+ printf("\033[36m%.9s\033[0m\n", line);
+
+ char *label = parse_label(&line),
+ *mn = parse_inst(&line);
+ int32_t mnemonic = -1;
+
+ if (label)
+ {
+ map_set(labels, label, (void *)num_insts);
+ printf("Set label %s at %lu\n", label, num_insts);
+ }
+
+ if (mn)
+ {
+#define MN(a) if (!strcasecmp(mn, #a)) \
+ mnemonic = a; \
+ else
+
+ MNEMONICS;
+#undef MN
+
+ printf("Got instruction %s %d\n", mn, mnemonic);
+
+ inst_t arg;
+ // printf("Parsing '%s'\n", line);
+#define INST(_mn, am, op, len) \
+ if (mnemonic == _mn && parse_arg(line, am, &arg)) \
+ { \
+ arg.opcode = op; \
+ print_inst(&arg); \
+ } \
+ else
+
+ INSTRUCTIONS
+ {
+ printf("\033[31mCould not be parsed: %s '%s'\033[0m\n", mn, line);
+ }
+#undef INST
+ }
+
+ num_insts++;
+ line = strtok(NULL, "\r\n");
+ }
+
+ free_map(labels);
+
+ return num_insts;
+}