ref: 75ce230dced14c4a622d20e41738474193a8817a
dir: /src/asm/rpn.c/
/*
* This file is part of RGBDS.
*
* Copyright (c) 1997-2018, Carsten Sorensen and RGBDS contributors.
*
* SPDX-License-Identifier: MIT
*/
/*
* Controls RPN expressions for objectfiles
*/
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "asm/main.h"
#include "asm/output.h"
#include "asm/rpn.h"
#include "asm/section.h"
#include "asm/symbol.h"
#include "asm/warning.h"
#include "opmath.h"
/* Makes an expression "not known", also setting its error message */
#define makeUnknown(expr_, ...) do { \
struct Expression *_expr = expr_; \
_expr->isKnown = false; \
/* If we had `asprintf` this would be great, but alas. */ \
_expr->reason = malloc(128); /* Use an initial reasonable size */ \
if (!_expr->reason) \
fatalerror("Can't allocate err string: %s\n", strerror(errno)); \
int size = snprintf(_expr->reason, 128, __VA_ARGS__); \
if (size >= 128) { /* If this wasn't enough, try again */ \
_expr->reason = realloc(_expr->reason, size + 1); \
sprintf(_expr->reason, __VA_ARGS__); \
} \
} while (0)
static uint8_t *reserveSpace(struct Expression *expr, uint32_t size)
{
/* This assumes the RPN length is always less than the capacity */
if (expr->rpnCapacity - expr->rpnLength < size) {
/* If there isn't enough room to reserve the space, realloc */
if (!expr->rpn)
expr->rpnCapacity = 256; /* Initial size */
while (expr->rpnCapacity - expr->rpnLength < size) {
if (expr->rpnCapacity >= MAXRPNLEN)
/*
* To avoid generating humongous object files, cap the
* size of RPN expressions
*/
fatalerror("RPN expression cannot grow larger than "
EXPAND_AND_STR(MAXRPNLEN) " bytes\n");
else if (expr->rpnCapacity > MAXRPNLEN / 2)
expr->rpnCapacity = MAXRPNLEN;
else
expr->rpnCapacity *= 2;
}
expr->rpn = realloc(expr->rpn, expr->rpnCapacity);
if (!expr->rpn)
fatalerror("Failed to grow RPN expression: %s\n", strerror(errno));
}
uint8_t *ptr = expr->rpn + expr->rpnLength;
expr->rpnLength += size;
return ptr;
}
/*
* Init a RPN expression
*/
static void rpn_Init(struct Expression *expr)
{
expr->reason = NULL;
expr->isKnown = true;
expr->isSymbol = false;
expr->rpn = NULL;
expr->rpnCapacity = 0;
expr->rpnLength = 0;
expr->rpnPatchSize = 0;
}
/*
* Free the RPN expression
*/
void rpn_Free(struct Expression *expr)
{
free(expr->rpn);
free(expr->reason);
rpn_Init(expr);
}
/*
* Add symbols, constants and operators to expression
*/
void rpn_Number(struct Expression *expr, uint32_t i)
{
rpn_Init(expr);
expr->val = i;
}
void rpn_Symbol(struct Expression *expr, char const *symName)
{
struct Symbol *sym = sym_FindScopedSymbol(symName);
if (sym_IsPC(sym) && !sect_GetSymbolSection()) {
error("PC has no value outside a section\n");
rpn_Number(expr, 0);
} else if (!sym || !sym_IsConstant(sym)) {
rpn_Init(expr);
expr->isSymbol = true;
makeUnknown(expr, sym_IsPC(sym) ? "PC is not constant at assembly time"
: "'%s' is not constant at assembly time", symName);
sym = sym_Ref(symName);
expr->rpnPatchSize += 5; /* 1-byte opcode + 4-byte symbol ID */
size_t nameLen = strlen(sym->name) + 1; /* Don't forget NUL! */
uint8_t *ptr = reserveSpace(expr, nameLen + 1);
*ptr++ = RPN_SYM;
memcpy(ptr, sym->name, nameLen);
} else {
rpn_Number(expr, sym_GetConstantValue(symName));
}
}
void rpn_BankSelf(struct Expression *expr)
{
rpn_Init(expr);
if (!currentSection) {
error("PC has no bank outside a section\n");
expr->val = 1;
} else if (currentSection->bank == (uint32_t)-1) {
makeUnknown(expr, "Current section's bank is not known");
expr->rpnPatchSize++;
*reserveSpace(expr, 1) = RPN_BANK_SELF;
} else {
expr->val = currentSection->bank;
}
}
void rpn_BankSymbol(struct Expression *expr, char const *symName)
{
struct Symbol const *sym = sym_FindScopedSymbol(symName);
/* The @ symbol is treated differently. */
if (sym_IsPC(sym)) {
rpn_BankSelf(expr);
return;
}
rpn_Init(expr);
if (sym && !sym_IsLabel(sym)) {
error("BANK argument must be a label\n");
} else {
sym = sym_Ref(symName);
assert(sym); // If the symbol didn't exist, it should have been created
if (sym_GetSection(sym) && sym_GetSection(sym)->bank != (uint32_t)-1) {
/* Symbol's section is known and bank is fixed */
expr->val = sym_GetSection(sym)->bank;
} else {
makeUnknown(expr, "\"%s\"'s bank is not known", symName);
expr->rpnPatchSize += 5; /* opcode + 4-byte sect ID */
size_t nameLen = strlen(sym->name) + 1; /* Room for NUL! */
uint8_t *ptr = reserveSpace(expr, nameLen + 1);
*ptr++ = RPN_BANK_SYM;
memcpy(ptr, sym->name, nameLen);
}
}
}
void rpn_BankSection(struct Expression *expr, char const *sectionName)
{
rpn_Init(expr);
struct Section *section = out_FindSectionByName(sectionName);
if (section && section->bank != (uint32_t)-1) {
expr->val = section->bank;
} else {
makeUnknown(expr, "Section \"%s\"'s bank is not known", sectionName);
size_t nameLen = strlen(sectionName) + 1; /* Room for NUL! */
uint8_t *ptr = reserveSpace(expr, nameLen + 1);
expr->rpnPatchSize += nameLen + 1;
*ptr++ = RPN_BANK_SECT;
memcpy(ptr, sectionName, nameLen);
}
}
void rpn_SizeOfSection(struct Expression *expr, char const *sectionName)
{
rpn_Init(expr);
makeUnknown(expr, "Section \"%s\"'s size is not known", sectionName);
size_t nameLen = strlen(sectionName) + 1; /* Room for NUL! */
uint8_t *ptr = reserveSpace(expr, nameLen + 1);
expr->rpnPatchSize += nameLen + 1;
*ptr++ = RPN_SIZEOF_SECT;
memcpy(ptr, sectionName, nameLen);
}
void rpn_StartOfSection(struct Expression *expr, char const *sectionName)
{
rpn_Init(expr);
makeUnknown(expr, "Section \"%s\"'s start is not known", sectionName);
size_t nameLen = strlen(sectionName) + 1; /* Room for NUL! */
uint8_t *ptr = reserveSpace(expr, nameLen + 1);
expr->rpnPatchSize += nameLen + 1;
*ptr++ = RPN_STARTOF_SECT;
memcpy(ptr, sectionName, nameLen);
}
void rpn_CheckHRAM(struct Expression *expr, const struct Expression *src)
{
*expr = *src;
expr->isSymbol = false;
if (!rpn_isKnown(expr)) {
expr->rpnPatchSize++;
*reserveSpace(expr, 1) = RPN_HRAM;
} else if (expr->val >= 0xFF00 && expr->val <= 0xFFFF) {
/* That range is valid, but only keep the lower byte */
expr->val &= 0xFF;
} else if (expr->val < 0 || expr->val > 0xFF) {
error("Source address $%" PRIx32 " not between $FF00 to $FFFF\n", expr->val);
}
}
void rpn_CheckRST(struct Expression *expr, const struct Expression *src)
{
*expr = *src;
if (rpn_isKnown(expr)) {
/* A valid RST address must be masked with 0x38 */
if (expr->val & ~0x38)
error("Invalid address $%" PRIx32 " for RST\n", expr->val);
/* The target is in the "0x38" bits, all other bits are set */
expr->val |= 0xC7;
} else {
expr->rpnPatchSize++;
*reserveSpace(expr, 1) = RPN_RST;
}
}
/*
* Checks that an RPN expression's value fits within N bits (signed or unsigned)
*/
void rpn_CheckNBit(struct Expression const *expr, uint8_t n)
{
assert(n != 0); // That doesn't make sense
assert(n < CHAR_BIT * sizeof(int)); // Otherwise `1 << n` is UB
if (rpn_isKnown(expr)) {
int32_t val = expr->val;
if (val < -(1 << (n - 1)) || val >= 1 << n)
warning(WARNING_TRUNCATION, "Expression must be %u-bit\n", n);
}
}
int32_t rpn_GetConstVal(struct Expression const *expr)
{
if (!rpn_isKnown(expr)) {
error("Expected constant expression: %s\n", expr->reason);
return 0;
}
return expr->val;
}
void rpn_LOGNOT(struct Expression *expr, const struct Expression *src)
{
*expr = *src;
expr->isSymbol = false;
if (rpn_isKnown(expr)) {
expr->val = !expr->val;
} else {
expr->rpnPatchSize++;
*reserveSpace(expr, 1) = RPN_LOGUNNOT;
}
}
struct Symbol const *rpn_SymbolOf(struct Expression const *expr)
{
if (!rpn_isSymbol(expr))
return NULL;
return sym_FindScopedSymbol((char *)expr->rpn + 1);
}
bool rpn_IsDiffConstant(struct Expression const *src, struct Symbol const *sym)
{
/* Check if both expressions only refer to a single symbol */
struct Symbol const *sym1 = rpn_SymbolOf(src);
if (!sym1 || !sym || sym1->type != SYM_LABEL || sym->type != SYM_LABEL)
return false;
struct Section const *section1 = sym_GetSection(sym1);
struct Section const *section2 = sym_GetSection(sym);
return section1 && (section1 == section2);
}
static bool isDiffConstant(struct Expression const *src1,
struct Expression const *src2)
{
return rpn_IsDiffConstant(src1, rpn_SymbolOf(src2));
}
void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
const struct Expression *src1, const struct Expression *src2)
{
expr->isSymbol = false;
/* First, check if the expression is known */
expr->isKnown = src1->isKnown && src2->isKnown;
if (expr->isKnown) {
rpn_Init(expr); /* Init the expression to something sane */
/* If both expressions are known, just compute the value */
uint32_t uleft = src1->val, uright = src2->val;
switch (op) {
case RPN_LOGOR:
expr->val = src1->val || src2->val;
break;
case RPN_LOGAND:
expr->val = src1->val && src2->val;
break;
case RPN_LOGEQ:
expr->val = src1->val == src2->val;
break;
case RPN_LOGGT:
expr->val = src1->val > src2->val;
break;
case RPN_LOGLT:
expr->val = src1->val < src2->val;
break;
case RPN_LOGGE:
expr->val = src1->val >= src2->val;
break;
case RPN_LOGLE:
expr->val = src1->val <= src2->val;
break;
case RPN_LOGNE:
expr->val = src1->val != src2->val;
break;
case RPN_ADD:
expr->val = uleft + uright;
break;
case RPN_SUB:
expr->val = uleft - uright;
break;
case RPN_XOR:
expr->val = src1->val ^ src2->val;
break;
case RPN_OR:
expr->val = src1->val | src2->val;
break;
case RPN_AND:
expr->val = src1->val & src2->val;
break;
case RPN_SHL:
if (src2->val < 0)
warning(WARNING_SHIFT_AMOUNT,
"Shifting left by negative amount %" PRId32 "\n",
src2->val);
if (src2->val >= 32)
warning(WARNING_SHIFT_AMOUNT,
"Shifting left by large amount %" PRId32 "\n", src2->val);
expr->val = op_shift_left(src1->val, src2->val);
break;
case RPN_SHR:
if (src1->val < 0)
warning(WARNING_SHIFT,
"Shifting right negative value %" PRId32 "\n", src1->val);
if (src2->val < 0)
warning(WARNING_SHIFT_AMOUNT,
"Shifting right by negative amount %" PRId32 "\n",
src2->val);
if (src2->val >= 32)
warning(WARNING_SHIFT_AMOUNT,
"Shifting right by large amount %" PRId32 "\n",
src2->val);
expr->val = op_shift_right(src1->val, src2->val);
break;
case RPN_MUL:
expr->val = uleft * uright;
break;
case RPN_DIV:
if (src2->val == 0)
fatalerror("Division by zero\n");
if (src1->val == INT32_MIN && src2->val == -1) {
warning(WARNING_DIV,
"Division of %" PRId32 " by -1 yields %" PRId32 "\n",
INT32_MIN, INT32_MIN);
expr->val = INT32_MIN;
} else {
expr->val = op_divide(src1->val, src2->val);
}
break;
case RPN_MOD:
if (src2->val == 0)
fatalerror("Modulo by zero\n");
if (src1->val == INT32_MIN && src2->val == -1)
expr->val = 0;
else
expr->val = op_modulo(src1->val, src2->val);
break;
case RPN_EXP:
if (src2->val < 0)
fatalerror("Exponentiation by negative power\n");
if (src1->val == INT32_MIN && src2->val == -1)
expr->val = 0;
else
expr->val = op_exponent(src1->val, src2->val);
break;
case RPN_UNSUB:
case RPN_UNNOT:
case RPN_LOGUNNOT:
case RPN_BANK_SYM:
case RPN_BANK_SECT:
case RPN_BANK_SELF:
case RPN_SIZEOF_SECT:
case RPN_STARTOF_SECT:
case RPN_HRAM:
case RPN_RST:
case RPN_CONST:
case RPN_SYM:
fatalerror("%d is not a binary operator\n", op);
}
} else if (op == RPN_SUB && isDiffConstant(src1, src2)) {
struct Symbol const *symbol1 = rpn_SymbolOf(src1);
struct Symbol const *symbol2 = rpn_SymbolOf(src2);
expr->val = sym_GetValue(symbol1) - sym_GetValue(symbol2);
expr->isKnown = true;
} else {
/* If it's not known, start computing the RPN expression */
/* Convert the left-hand expression if it's constant */
if (src1->isKnown) {
uint32_t lval = src1->val;
uint8_t bytes[] = {RPN_CONST, lval, lval >> 8,
lval >> 16, lval >> 24};
expr->rpnPatchSize = sizeof(bytes);
expr->rpn = NULL;
expr->rpnCapacity = 0;
expr->rpnLength = 0;
memcpy(reserveSpace(expr, sizeof(bytes)), bytes,
sizeof(bytes));
/* Use the other expression's un-const reason */
expr->reason = src2->reason;
free(src1->reason);
} else {
/* Otherwise just reuse its RPN buffer */
expr->rpnPatchSize = src1->rpnPatchSize;
expr->rpn = src1->rpn;
expr->rpnCapacity = src1->rpnCapacity;
expr->rpnLength = src1->rpnLength;
expr->reason = src1->reason;
free(src2->reason);
}
/* Now, merge the right expression into the left one */
uint8_t *ptr = src2->rpn; /* Pointer to the right RPN */
uint32_t len = src2->rpnLength; /* Size of the right RPN */
uint32_t patchSize = src2->rpnPatchSize;
/* If the right expression is constant, merge a shim instead */
uint32_t rval = src2->val;
uint8_t bytes[] = {RPN_CONST, rval, rval >> 8, rval >> 16,
rval >> 24};
if (src2->isKnown) {
ptr = bytes;
len = sizeof(bytes);
patchSize = sizeof(bytes);
}
/* Copy the right RPN and append the operator */
uint8_t *buf = reserveSpace(expr, len + 1);
memcpy(buf, ptr, len);
buf[len] = op;
free(src2->rpn); /* If there was none, this is `free(NULL)` */
expr->rpnPatchSize += patchSize + 1;
}
}
void rpn_HIGH(struct Expression *expr, const struct Expression *src)
{
*expr = *src;
expr->isSymbol = false;
if (rpn_isKnown(expr)) {
expr->val = (uint32_t)expr->val >> 8 & 0xFF;
} else {
uint8_t bytes[] = {RPN_CONST, 8, 0, 0, 0, RPN_SHR,
RPN_CONST, 0xFF, 0, 0, 0, RPN_AND};
expr->rpnPatchSize += sizeof(bytes);
memcpy(reserveSpace(expr, sizeof(bytes)), bytes, sizeof(bytes));
}
}
void rpn_LOW(struct Expression *expr, const struct Expression *src)
{
*expr = *src;
expr->isSymbol = false;
if (rpn_isKnown(expr)) {
expr->val = expr->val & 0xFF;
} else {
uint8_t bytes[] = {RPN_CONST, 0xFF, 0, 0, 0, RPN_AND};
expr->rpnPatchSize += sizeof(bytes);
memcpy(reserveSpace(expr, sizeof(bytes)), bytes, sizeof(bytes));
}
}
void rpn_ISCONST(struct Expression *expr, const struct Expression *src)
{
rpn_Init(expr);
expr->val = rpn_isKnown(src);
expr->isKnown = true;
expr->isSymbol = false;
}
void rpn_UNNEG(struct Expression *expr, const struct Expression *src)
{
*expr = *src;
expr->isSymbol = false;
if (rpn_isKnown(expr)) {
expr->val = -(uint32_t)expr->val;
} else {
expr->rpnPatchSize++;
*reserveSpace(expr, 1) = RPN_UNSUB;
}
}
void rpn_UNNOT(struct Expression *expr, const struct Expression *src)
{
*expr = *src;
expr->isSymbol = false;
if (rpn_isKnown(expr)) {
expr->val = ~expr->val;
} else {
expr->rpnPatchSize++;
*reserveSpace(expr, 1) = RPN_UNNOT;
}
}