scc

simple C compiler
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commit 9097ba1b790c0387f2d6fc6d3a99ec2b98f97679
parent 605e945e14e16e7a8d9855a8fc49749a48a0c6db
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Fri, 22 Sep 2017 08:43:16 +0200

[as] Remove Arg type

We only need an array of Node* because this is what the expression
evaluator is returning.

Diffstat:
as/as.h | 12+++---------
as/ins.c | 22++++++++++++----------
as/main.c | 6+++---
as/parser.c | 44+++++++++++---------------------------------
4 files changed, 29 insertions(+), 55 deletions(-)

diff --git a/as/as.h b/as/as.h @@ -39,11 +39,10 @@ enum endianess { typedef struct ins Ins; typedef struct op Op; -typedef struct arg Arg; -typedef void Format(Op *, Arg *); typedef struct section Section; typedef struct symbol Symbol; typedef struct node Node; +typedef void Format(Op *, Node **); struct line { char *label; @@ -59,16 +58,11 @@ struct ins { struct op { unsigned char flags; char size; - void (*format)(Op *, Arg *); + void (*format)(Op *, Node **); char *bytes; unsigned char *args; }; -struct arg { - unsigned char type; - TUINT val; -}; - struct section { char *name; char *mem; @@ -110,7 +104,7 @@ extern Symbol *lookup(char *name); extern Symbol *deflabel(char *name); /* parser.c */ -extern Arg *getargs(char *s); +extern Node **getargs(char *s); extern void error(char *msg, ...); /* Avoid errors in files where stdio is not included */ #ifdef stdin diff --git a/as/ins.c b/as/ins.c @@ -4,47 +4,49 @@ static char sccsid[] = "@(#) ./as/ins.c"; #include "as.h" void -direct(Op *op, Arg *args) +direct(Op *op, Node **args) { emit(cursec, op->bytes, op->size); } void -def(Arg *args, int siz) +def(Node **args, int siz) { - for ( ; args->type; ++args) - emit(cursec, pack(args->val, siz, endian), siz); + Node *np; + + for ( ; np = *args; ++args) + emit(cursec, pack(np->sym->value, siz, endian), siz); } void -defb(Op *op, Arg *args) +defb(Op *op, Node **args) { def(args, 1); } void -defw(Op *op, Arg *args) +defw(Op *op, Node **args) { def(args, 2); } void -defd(Op *op, Arg *args) +defd(Op *op, Node **args) { def(args, 4); } void -defq(Op *op, Arg *args) +defq(Op *op, Node **args) { def(args, 8); } void -equ(Op *op, Arg *args) +equ(Op *op, Node **args) { if (!linesym) error("label definition lacks a label"); else - linesym->value = args->val; + linesym->value = (*args)->sym->value; } diff --git a/as/main.c b/as/main.c @@ -8,7 +8,7 @@ static char sccsid[] = "@(#) ./as/main.c"; #include "as.h" int -match(Op *op, Arg *args) +match(Op *op, Node **args) { return 1; } @@ -26,8 +26,8 @@ as(char *text, char *xargs) { Ins *ins; Op *op, *lim; - Arg *args; - + Node **args; + ins = bsearch(text, instab, nr_ins, sizeof(Ins), cmp); if (!ins) { error("invalid instruction"); diff --git a/as/parser.c b/as/parser.c @@ -32,55 +32,33 @@ error(char *msg, ...) die("as: too many errors"); } -static Arg -number(char *s, int base) -{ - Arg arg; - TUINT n; - - /* TODO: Check overflow here */ - arg.type = AIMM; - for (n = 0; *s; n += *s++ - '0') - n *= base; - arg.val = n; - - return arg; -} - -Arg * +Node ** getargs(char *s) { char *t; int ch, len; - Arg *ap; - static Arg args[NARGS]; + Node **ap; + static Node *args[NARGS]; - for (ap = args; s; ++ap) { + if (!s) + return NULL; + + for (ap = args; ; *ap++ = expr(t)) { while (isspace(*s)) ++s; if (*s == '\0') break; if (ap == &args[NARGS-1]) - die("too many arguments in one instruction"); + error("too many arguments in one instruction"); for (t = s; *s && *s != ','; s++) /* nothing */; + *s++ = '\0'; len = t - s; if (len == 0) - goto wrong_operand; - - if (*s) - *s++ = '\0'; - - ch = *t; - if (isdigit(ch)) { - *ap = number(t, (s[len-1] == 'H') ? 16 : 10); - continue; - } -wrong_operand: - error("wrong operand '%s'", t); + error("wrong operand '%s'", t); } - ap->type = 0; + *ap = NULL; return args; }