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rmac/sect.c

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//
// RMAC - Reboot's Macro Assembler for all Atari computers
// SECT.C - Code Generation, Fixups and Section Management
// Copyright (C) 199x Landon Dyer, 2011-2018 Reboot and Friends
// RMAC derived from MADMAC v1.07 Written by Landon Dyer, 1986
// Source utilised with the kind permission of Landon Dyer
//
#include "sect.h"
#include "6502.h"
#include "direct.h"
#include "error.h"
#include "expr.h"
#include "listing.h"
#include "mach.h"
#include "mark.h"
#include "riscasm.h"
#include "symbol.h"
#include "token.h"
// Function prototypes
void MakeSection(int, uint16_t);
void SwitchSection(int);
// Section descriptors
SECT sect[NSECTS]; // All sections...
int cursect; // Current section number
// These are copied from the section descriptor, the current code chunk
// descriptor and the current fixup chunk descriptor when a switch is made into
// a section. They are copied back to the descriptors when the section is left.
uint16_t scattr; // Section attributes
uint32_t sloc; // Current loc in section
CHUNK * scode; // Current (last) code chunk
uint32_t challoc; // # bytes alloc'd to code chunk
uint32_t ch_size; // # bytes used in code chunk
uint8_t * chptr; // Deposit point in code chunk buffer
uint8_t * chptr_opcode; // Backup of chptr, updated before entering code generators
// Return a size (SIZB, SIZW, SIZL) or 0, depending on what kind of fixup is
// associated with a location.
static uint8_t fusiztab[] = {
0, // FU_QUICK
1, // FU_BYTE
2, // FU_WORD
2, // FU_WBYTE
4, // FU_LONG
1, // FU_BBRA
0, // (unused)
1, // FU_6BRA
};
// Offset to REAL fixup location
static uint8_t fusizoffs[] = {
0, // FU_QUICK
0, // FU_BYTE
0, // FU_WORD
1, // FU_WBYTE
0, // FU_LONG
1, // FU_BBRA
0, // (unused)
0, // FU_6BRA
};
//
// Initialize sections; setup initial ABS, TEXT, DATA and BSS sections
//
void InitSection(void)
{
// Initialize all sections
for(int i=0; i<NSECTS; i++)
MakeSection(i, 0);
// Construct default sections, make TEXT the current section
MakeSection(ABS, SUSED | SABS | SBSS); // ABS
MakeSection(TEXT, SUSED | TEXT ); // TEXT
MakeSection(DATA, SUSED | DATA ); // DATA
MakeSection(BSS, SUSED | BSS | SBSS); // BSS
MakeSection(M6502, SUSED | TEXT ); // 6502 code section
// Switch to TEXT for starters
SwitchSection(TEXT);
}
//
// Make a new (clean) section
//
void MakeSection(int sno, uint16_t attr)
{
SECT * p = &sect[sno];
p->scattr = attr;
p->sloc = 0;
p->orgaddr = 0;
p->scode = p->sfcode = NULL;
p->sfix = p->sffix = NULL;
}
//
// Switch to another section (copy section & chunk descriptors to global vars
// for fast access)
//
void SwitchSection(int sno)
{
CHUNK * cp;
cursect = sno;
SECT * p = &sect[sno];
m6502 = (sno == M6502); // Set 6502-mode flag
// Copy section vars
scattr = p->scattr;
sloc = p->sloc;
scode = p->scode;
orgaddr = p->orgaddr;
// Copy code chunk vars
if ((cp = scode) != NULL)
{
challoc = cp->challoc;
ch_size = cp->ch_size;
chptr = cp->chptr + ch_size;
// For 6502 mode, add the last org'd address
if (m6502)
chptr = cp->chptr + orgaddr;
}
else
challoc = ch_size = 0;
}
//
// Save current section
//
void SaveSection(void)
{
SECT * p = &sect[cursect];
p->scattr = scattr; // Bailout section vars
p->sloc = sloc;
p->orgaddr = orgaddr;
if (scode != NULL) // Bailout code chunk
scode->ch_size = ch_size;
}
//
// Test to see if a location has a fixup set on it. This is used by the
// listing generator to print 'xx's instead of '00's for forward references
//
int fixtest(int sno, uint32_t loc)
{
// Force update to sect[] variables
StopMark();
// Ugly linear search for a mark on our location. The speed doesn't
// matter, since this is only done when generating a listing, which is
// SLOW anyway.
for(FIXUP * fp=sect[sno].sffix; fp!=NULL; fp=fp->next)
{
uint32_t w = fp->attr;
uint32_t xloc = fp->loc + (int)fusizoffs[w & FUMASK];
if (xloc == loc)
return (int)fusiztab[w & FUMASK];
}
return 0;
}
//
// Check that there are at least 'amt' bytes left in the current chunk. If
// there are not, allocate another chunk of at least CH_CODE_SIZE bytes or
// 'amt', whichever is larger.
//
// If 'amt' is zero, ensure there are at least CH_THRESHOLD bytes, likewise.
//
void chcheck(uint32_t amt)
{
DEBUG { printf("chcheck(%u)\n", amt); }
// If in BSS section, no allocation required
if (scattr & SBSS)
return;
if (amt == 0)
amt = CH_THRESHOLD;
DEBUG { printf(" challoc=%i, ch_size=%i, diff=%i\n", challoc, ch_size, challoc - ch_size); }
if ((int)(challoc - ch_size) >= (int)amt)
return;
if (amt < CH_CODE_SIZE)
amt = CH_CODE_SIZE;
DEBUG { printf(" amt (adjusted)=%u\n", amt); }
SECT * p = &sect[cursect];
CHUNK * cp = malloc(sizeof(CHUNK) + amt);
// First chunk in section
if (scode == NULL)
{
cp->chprev = NULL;
p->sfcode = cp;
}
// Add chunk to other chunks
else
{
cp->chprev = scode;
scode->chnext = cp;
scode->ch_size = ch_size; // Save old chunk's globals
}
// Setup chunk and global vars
cp->chloc = sloc;
cp->chnext = NULL;
challoc = cp->challoc = amt;
ch_size = cp->ch_size = 0;
chptr = cp->chptr = ((uint8_t *)cp) + sizeof(CHUNK);
scode = p->scode = cp;
return;
}
//
// Arrange for a fixup on a location
//
int AddFixup(uint32_t attr, uint32_t loc, TOKEN * fexpr)
{
uint16_t exprlen = 0;
SYM * symbol = NULL;
uint32_t _orgaddr = 0;
// First, check to see if the expression is a bare label, otherwise, force
// the FU_EXPR flag into the attributes and count the tokens.
if ((fexpr[0] == SYMBOL) && (fexpr[2] == ENDEXPR))
{
symbol = symbolPtr[fexpr[1]];
// Save the org address for JR RISC instruction
if ((attr & FUMASKRISC) == FU_JR)
_orgaddr = orgaddr;
}
else
{
attr |= FU_EXPR;
exprlen = ExpressionLength(fexpr);
}
// Allocate space for the fixup + any expression
FIXUP * fixup = malloc(sizeof(FIXUP) + (sizeof(TOKEN) * exprlen));
// Store the relevant fixup information in the FIXUP
fixup->next = NULL;
fixup->attr = attr;
fixup->loc = loc;
fixup->fileno = cfileno;
fixup->lineno = curlineno;
fixup->expr = NULL;
fixup->symbol = symbol;
fixup->orgaddr = _orgaddr;
// Copy the passed in expression to the FIXUP, if any
if (exprlen > 0)
{
fixup->expr = (TOKEN *)((uint8_t *)fixup + sizeof(FIXUP));
memcpy(fixup->expr, fexpr, sizeof(TOKEN) * exprlen);
}
// Finally, put the FIXUP in the current section's linked list
if (sect[cursect].sffix == NULL)
{
sect[cursect].sffix = fixup;
sect[cursect].sfix = fixup;
}
else
{
sect[cursect].sfix->next = fixup;
sect[cursect].sfix = fixup;
}
DEBUG { printf("AddFixup: sno=%u, l#=%u, attr=$%X, loc=$%X, expr=%p, sym=%p, org=$%X\n", cursect, fixup->lineno, fixup->attr, fixup->loc, (void *)fixup->expr, (void *)fixup->symbol, fixup->orgaddr);
if (symbol != NULL)
printf(" name: %s, value: $%lX\n", symbol->sname, symbol->svalue);
}
return 0;
}
//
// Resolve fixups in the passed in section
//
int ResolveFixups(int sno)
{
SECT * sc = &sect[sno];
// "Cache" first chunk
CHUNK * cch = sc->sfcode;
// Can't fixup a section with nothing in it
if (cch == NULL)
return 0;
// Wire the 6502 segment's size to its allocated size (64K)
if (sno == M6502)
cch->ch_size = cch->challoc;
// Get first fixup for the passed in section
FIXUP * fixup = sect[sno].sffix;
while (fixup != NULL)
{
// We do it this way because we have continues everywhere... :-P
FIXUP * fup = fixup;
fixup = fixup->next;
uint32_t w = fup->attr; // Fixup long (type + modes + flags)
uint32_t loc = fup->loc; // Location to fixup
cfileno = fup->fileno;
curlineno = fup->lineno;
DEBUG { printf("ResolveFixups: sect#=%u, l#=%u, attr=$%X, loc=$%X, expr=%p, sym=%p, org=$%X\n", sno, fup->lineno, fup->attr, fup->loc, (void *)fup->expr, (void *)fup->symbol, fup->orgaddr); }
// This is based on global vars cfileno, curfname :-P
// This approach is kinda meh as well. I think we can do better
// than this.
SetFilenameForErrorReporting();
// Search for chunk containing location to fix up; compute a
// pointer to the location (in the chunk). Often we will find the
// Fixup is in the "cached" chunk, so the linear-search is seldom
// executed.
if (loc < cch->chloc || loc >= (cch->chloc + cch->ch_size))
{
for(cch=sc->sfcode; cch!=NULL; cch=cch->chnext)
{
if (loc >= cch->chloc && loc < (cch->chloc + cch->ch_size))
break;
}
if (cch == NULL)
{
// Fixup (loc) is out of range--this should never happen!
// Once we call this function, it winds down immediately; it
// doesn't return.
interror(7);
}
}
// Location to fix (in current chunk)
// We use the address of the chunk that loc is actually in, then
// subtract the chunk's starting location from loc to get the offset
// into the current chunk.
uint8_t * locp = cch->chptr + (loc - cch->chloc);
uint16_t eattr = 0; // Expression attrib
SYM * esym = NULL; // External symbol involved in expr
uint64_t eval; // Expression value
uint16_t flags; // Mark flags
// Compute expression/symbol value and attributes
// Complex expression
if (w & FU_EXPR)
{
if (evexpr(fup->expr, &eval, &eattr, &esym) != OK)
continue;
}
// Simple symbol
else
{
SYM * sy = fup->symbol;
eattr = sy->sattr;
if (eattr & DEFINED)
eval = sy->svalue;
else
eval = 0;
// If the symbol is not defined, but global, set esym to sy
if ((eattr & (GLOBAL | DEFINED)) == GLOBAL)
esym = sy;
}
uint16_t tdb = eattr & TDB;
// If the expression/symbol is undefined and no external symbol is
// involved, then that's an error.
if (!(eattr & DEFINED) && (esym == NULL))
{
error(undef_error);
continue;
}
// Do the fixup
//
// If a PC-relative fixup is undefined, its value is *not* subtracted
// from the location (that will happen in the linker when the external
// reference is resolved).
//
// MWC expects PC-relative things to have the LOC subtracted from the
// value, if the value is external (that is, undefined at this point).
//
// PC-relative fixups must be DEFINED and either in the same section
// (whereupon the subtraction takes place) or ABS (with no subtract).
if (w & FU_PCREL)
{
if (eattr & DEFINED)
{
if (tdb == sno)
eval -= loc;
else if (tdb)
{
// Allow cross-section PCREL fixups in Alcyon mode
if (prg_flag)
{
switch (tdb)
{
case TEXT:
// Shouldn't there be a break here, since otherwise, it will point to the DATA section?
// break;
case DATA:
eval += sect[TEXT].sloc;
break;
case BSS:
eval += sect[TEXT].sloc + sect[DATA].sloc;
break;
default:
error("invalid section");
break;
}
eval -= loc;
}
else
{
error("PC-relative expr across sections");
continue;
}
}
if (sbra_flag && (w & FU_LBRA) && (eval + 0x80 < 0x100))
warn("unoptimized short branch");
}
else if (obj_format == MWC)
eval -= loc;
tdb = 0;
eattr &= ~TDB;
}
// Handle fixup classes
switch (w & FUMASK)
{
// FU_BBRA fixes up a one-byte branch offset.
case FU_BBRA:
if (!(eattr & DEFINED))
{
error("external short branch");
continue;
}
eval -= 2;
if (eval + 0x80 >= 0x100)
goto rangeErr;
if (eval == 0)
{
if (CHECK_OPTS(OPT_NULL_BRA))
{
// Just output a NOP
*locp++ = 0x4E;
*locp = 0x71;
continue;
}
else
{
error("illegal bra.s with zero offset");
continue;
}
}
*++locp = (uint8_t)eval;
break;
// Fixup one-byte value at locp + 1.
case FU_WBYTE:
locp++;
// FALLTHROUGH
// Fixup one-byte forward references
case FU_BYTE:
if (!(eattr & DEFINED))
{
error("external byte reference");
continue;
}
if (tdb)
{
error("non-absolute byte reference");
continue;
}
if ((w & FU_PCREL) && ((eval + 0x80) >= 0x100))
goto rangeErr;
if (w & FU_SEXT)
{
if ((eval + 0x100) >= 0x200)
goto rangeErr;
}
else if (eval >= 0x100)
goto rangeErr;
*locp = (uint8_t)eval;
break;
// Fixup high/low byte off word for 6502
case FU_BYTEH:
if (!(eattr & DEFINED))
{
error("external byte reference");
continue;
}
*locp = (uint8_t)(eval >> 8);
break;
case FU_BYTEL:
if (!(eattr & DEFINED))
{
error("external byte reference");
continue;
}
*locp = (uint8_t)eval;
break;
// Fixup WORD forward references; the word could be unaligned in the
// section buffer, so we have to be careful.
case FU_WORD:
if ((w & FUMASKRISC) == FU_JR)
{
int reg;
if (fup->orgaddr)
reg = (signed)((eval - (fup->orgaddr + 2)) / 2);
else
reg = (signed)((eval - (loc + 2)) / 2);
if ((reg < -16) || (reg > 15))
{
error("relative jump out of range");
break;
}
*locp |= ((uint8_t)reg >> 3) & 0x03;
locp++;
*locp |= ((uint8_t)reg & 0x07) << 5;
break;
}
else if ((w & FUMASKRISC) == FU_NUM15)
{
if (((int)eval < -16) || ((int)eval > 15))
{
error("constant out of range (-16 - +15)");
break;
}
*locp |= ((uint8_t)eval >> 3) & 0x03;
locp++;
*locp |= ((uint8_t)eval & 0x07) << 5;
break;
}
else if ((w & FUMASKRISC) == FU_NUM31)
{
if (eval > 31)
{
error("constant out of range (0-31)");
break;
}
*locp |= ((uint8_t)eval >> 3) & 0x03;
locp++;
*locp |= ((uint8_t)eval & 0x07) << 5;
break;
}
else if ((w & FUMASKRISC) == FU_NUM32)
{
if ((eval < 1) || (eval > 32))
{
error("constant out of range (1-32)");
break;
}
if (w & FU_SUB32)
eval = (32 - eval);
eval = (eval == 32) ? 0 : eval;
*locp |= ((uint8_t)eval >> 3) & 0x03;
locp++;
*locp |= ((uint8_t)eval & 0x07) << 5;
break;
}
else if ((w & FUMASKRISC) == FU_REGONE)
{
if (eval > 31)
{
error("register one value out of range");
break;
}
*locp |= ((uint8_t)eval >> 3) & 0x03;
locp++;
*locp |= ((uint8_t)eval & 0x07) << 5;
break;
}
else if ((w & FUMASKRISC) == FU_REGTWO)
{
if (eval > 31)
{
error("register two value out of range");
break;
}
locp++;
*locp |= (uint8_t)eval & 0x1F;
break;
}
if (!(eattr & DEFINED))
{
flags = MWORD;
if (w & FU_PCREL)
flags |= MPCREL;
MarkRelocatable(sno, loc, 0, flags, esym);
}
else
{
if (tdb)
MarkRelocatable(sno, loc, tdb, MWORD, NULL);
if (w & FU_SEXT)
{
if (eval + 0x10000 >= 0x20000)
goto rangeErr;
}
else
{
// Range-check BRA and DBRA
if (w & FU_ISBRA)
{
if (eval + 0x8000 >= 0x10000)
goto rangeErr;
}
else if (eval >= 0x10000)
goto rangeErr;
}
}
// 6502 words are little endian, so handle that here
if (sno == M6502)
SETLE16(locp, 0, eval)
else
SETBE16(locp, 0, eval)
break;
// Fixup LONG forward references; the long could be unaligned in the
// section buffer, so be careful (again).
case FU_LONG:
flags = MLONG;
if ((w & FUMASKRISC) == FU_MOVEI)
{
// Long constant in MOVEI # is word-swapped, so fix it here
eval = WORDSWAP32(eval);
flags |= MMOVEI;
}
// If the symbol is undefined, make sure to pass the symbol in
// to the MarkRelocatable() function.
if (!(eattr & DEFINED))
MarkRelocatable(sno, loc, 0, flags, esym);
else if (tdb)
MarkRelocatable(sno, loc, tdb, flags, NULL);
SETBE32(locp, 0, eval);
break;
// Fixup QUAD forward references
// Need to add flags for OP uses... [DONE]
case FU_QUAD:
// If the symbol is undefined, make sure to pass the symbol in
// to the MarkRelocatable() function.
/* if (!(eattr & DEFINED))
MarkRelocatable(sno, loc, 0, MQUAD, esym);
else if (tdb)
MarkRelocatable(sno, loc, tdb, MQUAD, NULL);//*/
if (w & FU_OBJLINK)
{
uint64_t quad = GETBE64(locp, 0);
uint64_t addr = eval;
if (fup->orgaddr)
addr = fup->orgaddr;
//printf("sect.c: FU_OBJLINK quad=%016lX, addr=%016lX ", quad, addr);
eval = (quad & 0xFFFFFC0000FFFFFFLL) | ((addr & 0x3FFFF8) << 21);
//printf("(%016lX)\n", eval);
}
else if (w & FU_OBJDATA)
{
uint64_t quad = GETBE64(locp, 0);
uint64_t addr = eval;
if (fup->orgaddr)
addr = fup->orgaddr;
eval = (quad & 0x000007FFFFFFFFFFLL) | ((addr & 0xFFFFF8) << 40);
}
SETBE64(locp, 0, eval);
//printf("(%016lX)\n", eval);
break;
// Fixup a 3-bit "QUICK" reference in bits 9..1
// (range of 1..8) in a word. [Really bits 1..3 in a byte.]
case FU_QUICK:
if (!(eattr & DEFINED))
{
error("External quick reference");
continue;
}
if ((eval < 1) || (eval > 8))
goto rangeErr;
*locp |= (eval & 7) << 1;
break;
// Fix up 6502 funny branch
case FU_6BRA:
eval -= (loc + 1);
if (eval + 0x80 >= 0x100)
goto rangeErr;
*locp = (uint8_t)eval;
break;
// Fixup a 4-byte float
case FU_FLOATSING:
warn("FU_FLOATSING missing implementation\n%s", "And you may ask yourself, \"Self, how did I get here?\"");
break;
// Fixup a 8-byte float
case FU_FLOATDOUB:
warn("FU_FLOATDOUB missing implementation\n%s", "And you may ask yourself, \"Self, how did I get here?\"");
break;
// Fixup a 12-byte float
case FU_FLOATEXT:
warn("FU_FLOATEXT missing implementation\n%s", "And you may ask yourself, \"Self, how did I get here?\"");
break;
default:
// Bad fixup type--this should *never* happen!
// Once we call this function, it winds down immediately; it
// doesn't return.
interror(4);
}
continue;
rangeErr:
error("expression out of range");
}
return 0;
}
//
// Resolve all fixups
//
int ResolveAllFixups(void)
{
// Make undefined symbols GLOBL
if (glob_flag)
ForceUndefinedSymbolsGlobal();
DEBUG printf("Resolving TEXT sections...\n");
ResolveFixups(TEXT);
DEBUG printf("Resolving DATA sections...\n");
ResolveFixups(DATA);
DEBUG printf("Resolving 6502 sections...\n");
ResolveFixups(M6502); // Fixup 6502 section (if any)
return 0;
}
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