ref: db565b93a3e8db0e72be663d3cb6560ab96fc64f
dir: /src/cmd/as/ins.c/
#include <string.h> #include <scc/scc.h> #include "as.h" extern Section *sabs, *sbss, *sdata, *stext; enum { EQU, COMMON, SIZE, XSTRING, ASCII, TYPE, }; static void reloc(Symbol *sym, unsigned flags, unsigned size, unsigned nbits, unsigned shift) { } char * tobytes(TUINT v, int nbytes, int inc) { static char buf[sizeof(TUINT)]; int idx; idx = (inc < 0) ? nbytes-1 : 0; while (nbytes--) { buf[idx] = v; idx += inc; v >>= 8; } if (v) error("overflow in immediate value"); return buf; } void noargs(Op *op, Node **args) { emit(op->bytes, op->size); } static void xstring(int which, Node **args) { Node *np; char *s; size_t len; while (np = *args++) { s = np->sym->name.buf; len = strlen(s); len += which == XSTRING; emit(s, len); } } void string(Op *op, Node **args) { xstring(STRING, args); } void ascii(Op *op, Node **args) { xstring(STRING, args); } void def(Node **args, int siz) { Node *np; while (np = *args++) { Symbol *sym = np->sym; if ((sym->flags & FABS) == 0) reloc(sym, 0, siz, siz * 8, 0); emit(tobytes(sym->value, siz, endian), siz); } } void defb(Op *op, Node **args) { def(args, 1); } void defw(Op *op, Node **args) { def(args, 2); } void defd(Op *op, Node **args) { def(args, 4); } void defq(Op *op, Node **args) { def(args, 8); } static void symexp(int which, Op *op, Node **args) { Symbol *sym, *exp; static char *cmds[] = { [EQU] = "equ", [COMMON] = "common", [SIZE] = "size", }; char *cmd = cmds[which]; if (args[1]) { sym = args[0]->sym; exp = args[1]->sym; } else if (linesym) { sym = linesym; exp = args[0]->sym; } else { error("%s pseudo instruction lacks a label", cmd); } if ((exp->flags & FABS) == 0) error("%s expression is not an absolute expression", cmd); switch (which) { case EQU: if (pass == 1 && (sym->flags & FDEF)) error("redefinition of symbol '%s'", sym->name.buf); sym->value = exp->value; sym->flags |= FDEF; break; case COMMON: sym->flags |= FCOMMON; case SIZE: sym->size = exp->value; break; case TYPE: sym->type.buf = xstrdup(exp->name.buf); break; } } void equ(Op *op, Node **args) { symexp(EQU, op, args); } void common(Op *op, Node **args) { symexp(COMMON, op, args); } void size(Op *op, Node **args) { symexp(SIZE, op, args); } void type(Op *op, Node **args) { symexp(TYPE, op, args); } void section(Op *op, Node **args) { Symbol *sym = args[0]->sym; char *attr = NULL; if (args[1]) attr = args[1]->sym->name.buf; setsec(sym->name.buf, attr); } void text(Op *op, Node **args) { cursec = stext; } void data(Op *op, Node **args) { cursec = sdata; } void bss(Op *op, Node **args) { cursec = sbss; } void extrn(Op *op, Node **args) { Symbol *sym = args[0]->sym; sym->flags |= FEXTERN; } void global(Op *op, Node **args) { Symbol *sym = args[0]->sym; sym->flags |= FGLOBAL; } void align(Op *op, Node **args) { Symbol *sym = args[0]->sym; TUINT curpc, pc, al; if ((sym->flags & FABS) == 0) error("align expression is not an absolute expression"); if ((al = sym->value) == 0) return; al--; curpc = cursec->curpc; pc = curpc+al & ~al; for (al = pc - curpc; al > 0; --al) emit((char []) {0}, 1); } void end(Op *op, Node **args) { endpass = 1; } void include(Op *op, Node **args) { addinput(args[0]->sym->name.buf); }