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static void assemble_file(char *fname)
{
char *directive, *value, *p, *q, *special, *line, debugid[80];
insn output_ins;
int i, rn_error, validid;
long seg, offs;
struct tokenval tokval;
expr *e;
int pass, pass_max;
int pass_cnt = 0; /* count actual passes */
if (cmd_sb == 32 && cmd_cpu < IF_386)
report_error(ERR_FATAL, "command line: 32-bit segment size requires a higher cpu");
pass_max = (optimizing > 0 ? optimizing : 0) + 2; /* passes 1, optimizing, then 2 */
pass0 = !(optimizing > 0); /* start at 1 if not optimizing */
/* 正式进行指令汇编 */
for (pass = 1; pass <= pass_max && pass0 <= 2; pass++) { /* 没有优化的情况下是循环 2 遍，优化的情况下最多循环 4 遍 */
int pass1, pass2;
ldfunc def_label;
pass1 = pass < pass_max ? 1 : 2; /* seq is 1, 1, 1,..., 1, 2 */
pass2 = pass > 1 ? 2 : 1; /* seq is 1, 2, 2,..., 2, 2 */
/* pass0 seq is 0, 0, 0,..., 1, 2 */
def_label = pass > 1 ? redefine_label : define_label;
sb = cmd_sb; /* set 'bits' to command line default */
cpu = cmd_cpu;
if (pass0 == 2) {
if (*listname)
nasmlist.init(listname, report_error);
}
in_abs_seg = FALSE;
global_offset_changed = FALSE; /* set by redefine_label */
location.segment = ofmt->section(NULL, pass2, &sb); /* 获取代码段索引，并且将 sb 设置成 32 ,在这里， pass2 不起作用*/
if (pass > 1) { /* 估计是插入机器码用的 ？？？ */
saa_rewind(forwrefs);
forwref = saa_rstruct(forwrefs);
raa_free(offsets);
offsets = raa_init();
}
preproc->reset(fname, pass1, report_error, evaluate, &nasmlist);
globallineno = 0;
if (pass == 1)
location.known = TRUE;
location.offset = offs = GET_CURR_OFFS; /* #define GET_CURR_OFFS (in_abs_seg ? abs_offset : raa_read(offsets, location.segment)) */
while ((line = preproc->getline())) {
globallineno++;
/* here we parse our directives; this is not handled by the 'real'
* parser. */
directive = line;
if ((i = getkw(&directive, &value))) {
switch (i) {
case 1: /* [SEGMENT n] 例如:[SECTION .text] */
seg = ofmt->section(value, pass2, &sb); /* 建立相应的 section， 并获取其索引 */
if (seg == NO_SEG) {
report_error(pass1 == 1 ? ERR_NONFATAL : ERR_PANIC, "segment name `%s' not recognised", value);
} else {
in_abs_seg = FALSE;
location.segment = seg;
}
break;
case 2: /* [EXTERN label(:special) (size 计算式)] */
if (*value == '$')
value++; /* skip initial $ if present */
if (pass0 == 2) {
q = value;
while (*q && *q != ':')
q++;
if (*q == ':') {
*q++ = '\0';
ofmt->symdef(value, 0L, 0L, 3, q); /*
* 将变量名与属性取出放入 value 与 q 中，然后进行处理，参数 3 表示已经定义的全局变量
* global, extern 的符号最后插入
*/
}
} else if (pass == 1) { /* pass == 1 */
q = value;
validid = TRUE;
if (!isidstart(*q))
validid = FALSE;
while (*q && *q != ':') {
if (!isidchar(*q))
validid = FALSE;
q++;
}
if (!validid) { /* 判断是否符合变量声明规定 */
report_error(ERR_NONFATAL, "identifier expected after EXTERN");
break;
}
/* 通过 : 判断，将字符串的名字和属性分别放入 value 和 q 中 */
if (*q == ':') {
*q++ = '\0';
special = q;
} else
special = NULL;
if (!is_extern(value)) { /* allow re-EXTERN to be ignored */
int temp = pass0;
pass0 = 1; /* fake pass 1 in labels.c */
declare_as_global(value, special, report_error); /* 在这个函数，pass0 不起作用 */
define_label(value, seg_alloc(), 0L, NULL, FALSE, TRUE, ofmt, report_error);
pass0 = temp;
}
} /* else pass0 == 1 */
break;
case 3: /* [BITS bits] */
sb = get_bits(value);
break;
case 4: /* [GLOBAL symbol(:special) (size 计算式)] */
if (*value == '$')
value++; /* skip initial $ if present */
if (pass0 == 2) { /* pass 2 */
q = value;
while (*q && *q != ':')
q++;
if (*q == ':') {
*q++ = '\0';
ofmt->symdef(value, 0L, 0L, 3, q); /*
* 将变量名与属性取出放入 value 与 q 中，然后进行处理，参数 3 表示已经定义的全局变量
* global, extern 的符号最后插入
*/
}
} else if (pass2 == 1) { /* pass == 1 */
q = value;
validid = TRUE;
if (!isidstart(*q))
validid = FALSE;
while (*q && *q != ':') {
if (!isidchar(*q))
validid = FALSE;
q++;
}
if (!validid) {
report_error(ERR_NONFATAL, "identifier expected after GLOBAL");
break;
}
if (*q == ':') {
*q++ = '\0';
special = q;
} else
special = NULL;
declare_as_global(value, special, report_error);
} /* pass == 1 */
break;
case 5: /* [COMMON symbol size:special] */
if (*value == '$')
value++; /* skip initial $ if present */
if (pass0 == 1) {
p = value;
validid = TRUE;
if (!isidstart(*p))
validid = FALSE;
/* 获取 symbol */
while (*p && !isspace(*p)) {
if (!isidchar(*p))
validid = FALSE;
p++;
}
if (!validid) {
report_error(ERR_NONFATAL, "identifier expected after COMMON");
break;
}
if (*p) {
long size;
/* 获取 size */
while (*p && isspace(*p))
*p++ = '\0';
q = p;
while (*q && *q != ':')
q++;
/* 获取 special */
if (*q == ':') {
*q++ = '\0';
special = q;
} else
special = NULL;
size = readnum(p, &rn_error);
if (rn_error)
report_error(ERR_NONFATAL, "invalid size specified in COMMON declaration");
else
define_common(value, seg_alloc(), size, special, ofmt, report_error);
} else
report_error(ERR_NONFATAL, "no size specified in COMMON declaration");
} else if (pass0 == 2) { /* pass == 2 */
q = value;
while (*q && *q != ':') {
if (isspace(*q))
*q = '\0';
q++;
}
if (*q == ':') {
*q++ = '\0';
ofmt->symdef(value, 0L, 0L, 3, q);
}
}
break;
case 6: /* [ABSOLUTE address] */
stdscan_reset();
stdscan_bufptr = value;
tokval.t_type = TOKEN_INVALID;
e = evaluate(stdscan, NULL, &tokval, NULL, pass2, report_error, NULL);
if (e) {
if (!is_reloc(e))
report_error(pass0 == 1 ? ERR_NONFATAL : ERR_PANIC, "cannot use non-relocatable expression as ABSOLUTE address");
else {
abs_seg = reloc_seg(e);
abs_offset = reloc_value(e);
}
} else if (pass == 1)
abs_offset = 0x100; /* don't go near zero in case of / */
else
report_error(ERR_PANIC, "invalid ABSOLUTE address in pass two");
in_abs_seg = TRUE;
location.segment = NO_SEG;
break;
case 7: /* DEBUG */
p = value;
q = debugid;
validid = TRUE;
if (!isidstart(*p))
validid = FALSE;
while (*p && !isspace(*p)) {
if (!isidchar(*p))
validid = FALSE;
*q++ = *p++;
}
*q++ = 0;
if (!validid) {
report_error(pass == 1 ? ERR_NONFATAL : ERR_PANIC, "identifier expected after DEBUG");
break;
}
while (*p && isspace(*p))
p++;
if (pass == pass_max)
ofmt->current_dfmt->debug_directive(debugid, p);
break;
case 8: /* [WARNING {+|-}warn-name] */
if (pass1 == 1) {
while (*value && isspace(*value))
value++;
if (*value == '+' || *value == '-') {
validid = (*value == '-') ? TRUE : FALSE;
value++;
} else
validid = FALSE;
for (i = 1; i <= ERR_WARN_MAX; i++)
if (!nasm_stricmp(value, suppressed_names[i]))
break;
if (i <= ERR_WARN_MAX)
suppressed[i] = validid;
else
report_error(ERR_NONFATAL, "invalid warning id in WARNING directive");
}
break;
case 9: /* cpu */
cpu = get_cpu(value);
break;
case 10: /* fbk 9/2/00 *//* [LIST {+|-}] */ /* 在源代码中关闭或者开启 listing file 功能 */
while (*value && isspace(*value))
value++;
if (*value == '+') {
user_nolist = 0;
} else {
if (*value == '-') {
user_nolist = 1;
} else {
report_error(ERR_NONFATAL, "invalid parameter to \"list\" directive");
}
}
break;
default:
if (!ofmt->directive(directive, value, pass2))
report_error(pass1 == 1 ? ERR_NONFATAL : ERR_PANIC, "unrecognised directive [%s]", directive);
}
} else { /* it isn't a directive */ /* 处理非 directive */
parse_line(pass1, line, &output_ins, report_error, evaluate, def_label);
if (!(optimizing > 0) && pass == 2) {
if (forwref != NULL && globallineno == forwref->lineno) {
/* 在 pass == 2 的时候，设置 label forward 标记 */
output_ins.forw_ref = TRUE;
do {
output_ins.oprs[forwref->operand].opflags |= OPFLAG_FORWARD;
forwref = saa_rstruct(forwrefs);
} while (forwref != NULL && forwref->lineno == globallineno);
} else
output_ins.forw_ref = FALSE;
}
if (!(optimizing > 0) && output_ins.forw_ref) {
if (pass == 1) { /* 在 pass == 1 的时候，将 Forward Label 放入 forwrefs 中 */
for (i = 0; i < output_ins.operands; i++) {
if (output_ins.oprs[i].opflags & OPFLAG_FORWARD) {
struct forwrefinfo *fwinf = (struct forwrefinfo *) saa_wstruct(forwrefs);
fwinf->lineno = globallineno;
fwinf->operand = i;
}
}
} else { /* pass == 2 */
/*
* Hack to prevent phase error in the code
* rol ax,x
* x equ 1
*
* If the second operand is a forward reference,
* the UNITY property of the number 1 in that
* operand is cancelled. Otherwise the above
* sequence will cause a phase error.
*
* This hack means that the above code will
* generate 286+ code.
*
* The forward reference will mean that the
* operand will not have the UNITY property on
* the first pass, so the pass behaviours will
* be consistent.
*/
if (output_ins.operands >= 2 && (output_ins.oprs[1].opflags & OPFLAG_FORWARD))
{
output_ins.oprs[1].type &= ~(ONENESS | BYTENESS);
}
} /* pass == 2 */
}
/* forw_ref */
if (output_ins.opcode == I_EQU) {
if (pass1 == 1) { /* 处理 equ 指令，当作 label 处理 */
/*
* Special `..' EQUs get processed in pass two,
* except `..@' macro-processor EQUs which are done
* in the normal place.
*/
if (!output_ins.label)
report_error(ERR_NONFATAL, "EQU not preceded by label"); /* equ 0; 显示此出错信息 */
else if (output_ins.label[0] != '.' || output_ins.label[1] != '.' || output_ins.label[2] == '@') {
if (output_ins.operands == 1 &&
(output_ins.oprs[0].type & IMMEDIATE) &&
output_ins.oprs[0].wrt == NO_SEG) {
int isext = output_ins.oprs[0].opflags & OPFLAG_EXTERN;
def_label(output_ins.label,
output_ins.oprs[0].segment,
output_ins.oprs[0].offset, NULL,
FALSE, isext, ofmt, report_error);
} else if (output_ins.operands == 2 /* Temp: equ 0:3 ;segment:offset */
&& (output_ins.oprs[0].type & IMMEDIATE)
&& (output_ins.oprs[0].type & COLON)
&& output_ins.oprs[0].segment == NO_SEG
&& output_ins.oprs[0].wrt == NO_SEG
&& (output_ins.oprs[1].type & IMMEDIATE)
&& output_ins.oprs[1].segment == NO_SEG
&& output_ins.oprs[1].wrt == NO_SEG) {
def_label(output_ins.label,
output_ins.oprs[0].offset | SEG_ABS, /* 地址固定的参数 */
output_ins.oprs[1].offset, NULL,
FALSE, FALSE, ofmt, report_error);
} else
report_error(ERR_NONFATAL, "bad syntax for EQU");
}
} else { /* pass == 2 */
/*
* Special `..' EQUs get processed here, except
* `..@' macro processor EQUs which are done above.
*/
if (output_ins.label[0] == '.' && output_ins.label[1] == '.' && output_ins.label[2] != '@') {
if (output_ins.operands == 1 && (output_ins.oprs[0].type & IMMEDIATE)) {
define_label(output_ins.label,
output_ins.oprs[0].segment,
output_ins.oprs[0].offset, NULL,
FALSE, FALSE, ofmt, report_error);
} else if (output_ins.operands == 2
&& (output_ins.oprs[0].type & IMMEDIATE)
&& (output_ins.oprs[0].type & COLON)
&& output_ins.oprs[0].segment == NO_SEG
&& (output_ins.oprs[1].type & IMMEDIATE)
&& output_ins.oprs[1].segment == NO_SEG) {
define_label(output_ins.label,
output_ins.oprs[0].offset | SEG_ABS,
output_ins.oprs[1].offset, NULL,
FALSE, FALSE, ofmt, report_error);
} else
report_error(ERR_NONFATAL, "bad syntax for EQU");
}
} /* pass == 2 */
} else { /* instruction isn't an EQU */
if (pass1 == 1) { /* 主要是计算指令长度 */
long l = insn_size(location.segment, offs, sb, cpu, &output_ins, report_error);
/* if (using_debug_info) && output_ins.opcode != -1) */
if (using_debug_info)
{ /* fbk 03/25/01 */
/* this is done here so we can do debug type info */
long typeinfo = TYS_ELEMENTS(output_ins.operands);
switch (output_ins.opcode) {
case I_RESB:
typeinfo = TYS_ELEMENTS(output_ins.oprs[0].offset) | TY_BYTE;
break;
case I_RESW:
typeinfo = TYS_ELEMENTS(output_ins.oprs[0].offset) | TY_WORD;
break;
case I_RESD:
typeinfo = TYS_ELEMENTS(output_ins.oprs[0].offset) | TY_DWORD;
break;
case I_RESQ:
typeinfo = TYS_ELEMENTS(output_ins.oprs[0].offset) | TY_QWORD;
break;
case I_REST:
typeinfo = TYS_ELEMENTS(output_ins.oprs[0].offset) | TY_TBYTE;
break;
case I_DB:
typeinfo |= TY_BYTE;
break;
case I_DW:
typeinfo |= TY_WORD;
break;
case I_DD:
if (output_ins.eops_float)
typeinfo |= TY_FLOAT;
else
typeinfo |= TY_DWORD;
break;
case I_DQ:
typeinfo |= TY_QWORD;
break;
case I_DT:
typeinfo |= TY_TBYTE;
break;
default:
typeinfo = TY_LABEL;
}
ofmt->current_dfmt->debug_typevalue(typeinfo); /* 在该版本，此函数未实现 */
}
if (l != -1) {
offs += l;
SET_CURR_OFFS(offs);
}
/*
* else l == -1 => invalid instruction, which will be
* flagged as an error on pass 2
*/
} else { /* pass == 2 */ /* 汇编指令 */
offs += assemble(location.segment, offs, sb, cpu, &output_ins, ofmt, report_error, &nasmlist);
SET_CURR_OFFS(offs);
}
} /* not an EQU */
cleanup_insn(&output_ins);
}
nasm_free(line);
location.offset = offs = GET_CURR_OFFS;
} /* end while (line = preproc->getline... */
if (pass1 == 2 && global_offset_changed)
report_error(ERR_NONFATAL, "phase error detected at end of assembly.");
if (pass1 == 1)
preproc->cleanup(1);
if (pass1 == 1 && terminate_after_phase) {
fclose(ofile);
remove(outname);
if (want_usage)
usage();
exit(1);
}
pass_cnt++;
if (pass > 1 && !global_offset_changed) {
pass0++;
if (pass0 == 2)
pass = pass_max - 1;
} else if (!(optimizing > 0))
pass0++;
} /* for (pass=1; pass<=2; pass++) */
preproc->cleanup(0); /* pass = 0 */
nasmlist.cleanup();
#if 1
if (optimizing > 0 && opt_verbose_info) /* -On and -Ov switches */
fprintf(stdout, "info:: assembly required 1+%d+1 passes\n", pass_cnt - 2);
#endif
} /* exit from assemble_file (...) */
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