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Refactor some math functions into a shared file for rgbasm and rgblink

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Fixes #769

Fixes #770
This commit is contained in:
Rangi
2021-02-28 16:50:47 -05:00
committed by Eldred Habert
parent 0774f5eb9d
commit ac2cefdd87
7 changed files with 151 additions and 177 deletions
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6
Makefile
View File

@@ -72,7 +72,8 @@ rgbasm_obj := \
src/extern/getopt.o \
src/extern/utf8decoder.o \
src/hashmap.o \
src/linkdefs.o
src/linkdefs.o \
src/opmath.o
src/asm/lexer.o src/asm/main.o: src/asm/parser.h
@@ -88,7 +89,8 @@ rgblink_obj := \
src/extern/err.o \
src/extern/getopt.o \
src/hashmap.o \
src/linkdefs.o
src/linkdefs.o \
src/opmath.o
rgbfix_obj := \
src/fix/main.o \

20
include/opmath.h Normal file
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@@ -0,0 +1,20 @@
/*
* This file is part of RGBDS.
*
* Copyright (c) 1997-2021, RGBDS contributors.
*
* SPDX-License-Identifier: MIT
*/
#ifndef RGBDS_OP_MATH_H
#define RGBDS_OP_MATH_H
#include <stdint.h>
int32_t op_divide(int32_t dividend, int32_t divisor);
int32_t op_modulo(int32_t dividend, int32_t divisor);
int32_t op_exponent(int32_t base, uint32_t power);
int32_t op_shift_left(int32_t value, int32_t amount);
int32_t op_shift_right(int32_t value, int32_t amount);
#endif /* RGBDS_OP_MATH_H */

2
src/CMakeLists.txt
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@@ -60,6 +60,7 @@ set(rgbasm_src
"extern/utf8decoder.c"
"hashmap.c"
"linkdefs.c"
"opmath.c"
)
set(rgbfix_src
@@ -83,6 +84,7 @@ set(rgblink_src
"link/symbol.c"
"hashmap.c"
"linkdefs.c"
"opmath.c"
)
foreach(PROG "asm" "fix" "gfx" "link")

96
src/asm/rpn.c
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@@ -25,6 +25,8 @@
#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_; \
@@ -244,77 +246,6 @@ void rpn_LOGNOT(struct Expression *expr, const struct Expression *src)
}
}
static int32_t shift(int32_t shiftee, int32_t amount)
{
if (amount >= 0) {
// Left shift
if (amount >= 32) {
warning(WARNING_SHIFT_AMOUNT, "Shifting left by large amount %"
PRId32 "\n", amount);
return 0;
} else {
/*
* Use unsigned to force a bitwise shift
* Casting back is OK because the types implement two's
* complement behavior
*/
return (uint32_t)shiftee << amount;
}
} else {
// Right shift
amount = -amount;
if (amount >= 32) {
warning(WARNING_SHIFT_AMOUNT,
"Shifting right by large amount %" PRId32 "\n", amount);
return shiftee < 0 ? -1 : 0;
} else if (shiftee >= 0) {
return shiftee >> amount;
} else {
/*
* The C standard leaves shifting right negative values
* undefined, so use a left shift manually sign-extended
*/
return (uint32_t)shiftee >> amount
| -(UINT32_C(1) << (32 - amount));
}
}
}
static int32_t divide(int32_t dividend, int32_t divisor)
{
// Adjust division to floor toward negative infinity,
// not truncate toward zero
return dividend / divisor - ((dividend % divisor < 0) != (divisor < 0));
}
static int32_t modulo(int32_t dividend, int32_t divisor)
{
int32_t remainder = dividend % divisor;
// Adjust modulo to have the sign of the divisor,
// not the sign of the dividend
return remainder + divisor * ((remainder < 0) != (divisor < 0));
}
static int32_t exponent(int32_t base, uint32_t power)
{
int32_t result = 1;
for (;;) {
if (power % 2)
result *= base;
power /= 2;
if (!power)
break;
base *= base;
}
return result;
}
struct Symbol const *rpn_SymbolOf(struct Expression const *expr)
{
if (!rpn_isSymbol(expr))
@@ -400,11 +331,17 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
"Shifting left by negative amount %" PRId32 "\n",
src2->nVal);
expr->nVal = shift(src1->nVal, src2->nVal);
if (src2->nVal >= 32)
warning(WARNING_SHIFT_AMOUNT,
"Shifting left by large amount %" PRId32 "\n",
src2->nVal);
expr->nVal = op_shift_left(src1->nVal, src2->nVal);
break;
case RPN_SHR:
if (src1->nVal < 0)
warning(WARNING_SHIFT, "Shifting negative value %" PRId32 "\n",
warning(WARNING_SHIFT, "Shifting right negative value %"
PRId32 "\n",
src1->nVal);
if (src2->nVal < 0)
@@ -412,7 +349,12 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
"Shifting right by negative amount %" PRId32 "\n",
src2->nVal);
expr->nVal = shift(src1->nVal, -src2->nVal);
if (src2->nVal >= 32)
warning(WARNING_SHIFT_AMOUNT,
"Shifting right by large amount %" PRId32 "\n",
src2->nVal);
expr->nVal = op_shift_right(src1->nVal, src2->nVal);
break;
case RPN_MUL:
expr->nVal = uleft * uright;
@@ -426,7 +368,7 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
PRId32 "\n", INT32_MIN, INT32_MIN);
expr->nVal = INT32_MIN;
} else {
expr->nVal = divide(src1->nVal, src2->nVal);
expr->nVal = op_divide(src1->nVal, src2->nVal);
}
break;
case RPN_MOD:
@@ -436,7 +378,7 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
if (src1->nVal == INT32_MIN && src2->nVal == -1)
expr->nVal = 0;
else
expr->nVal = modulo(src1->nVal, src2->nVal);
expr->nVal = op_modulo(src1->nVal, src2->nVal);
break;
case RPN_EXP:
if (src2->nVal < 0)
@@ -445,7 +387,7 @@ void rpn_BinaryOp(enum RPNCommand op, struct Expression *expr,
if (src1->nVal == INT32_MIN && src2->nVal == -1)
expr->nVal = 0;
else
expr->nVal = exponent(src1->nVal, src2->nVal);
expr->nVal = op_exponent(src1->nVal, src2->nVal);
break;
case RPN_UNSUB:

84
src/link/patch.c
View File

@@ -18,82 +18,10 @@
#include "link/symbol.h"
#include "linkdefs.h"
#include "opmath.h"
#include "extern/err.h"
static int32_t divide(int32_t dividend, int32_t divisor)
{
// Adjust division to floor toward negative infinity,
// not truncate toward zero
return dividend / divisor - ((dividend % divisor < 0) != (divisor < 0));
}
static int32_t modulo(int32_t dividend, int32_t divisor)
{
int32_t remainder = dividend % divisor;
// Adjust modulo to have the sign of the divisor,
// not the sign of the dividend
return remainder + divisor * ((remainder < 0) != (divisor < 0));
}
static int32_t exponent(int32_t base, uint32_t power)
{
int32_t result = 1;
for (;;) {
if (power % 2)
result *= base;
power /= 2;
if (!power)
break;
base *= base;
}
return result;
}
static int32_t asl(int32_t value, int32_t shiftamt); // Forward decl for below
static int32_t asr(int32_t value, int32_t shiftamt)
{
uint32_t uvalue = value;
// Get the easy cases out of the way
if (shiftamt == 0)
return value;
if (value == 0 || shiftamt <= -32)
return 0;
if (shiftamt > 31)
return (value < 0) ? -1 : 0;
if (shiftamt < 0)
return asl(value, -shiftamt);
if (value > 0)
return uvalue >> shiftamt;
{
// Calculate an OR mask for sign extension
// 1->0x80000000, 2->0xC0000000, ..., 31->0xFFFFFFFE
uint32_t shiftamt_high_bits = -((uint32_t)1 << (32 - shiftamt));
return (uvalue >> shiftamt) | shiftamt_high_bits;
}
}
static int32_t asl(int32_t value, int32_t shiftamt)
{
// Repeat the easy cases here to avoid INT_MIN funny business
if (shiftamt == 0)
return value;
if (value == 0 || shiftamt >= 32)
return 0;
if (shiftamt < -31)
return (value < 0) ? -1 : 0;
if (shiftamt < 0)
return asr(value, -shiftamt);
return (uint32_t)value << shiftamt;
}
/*
* This is an "empty"-type stack. Apart from the actual values, we also remember
* whether the value is a placeholder inserted for error recovery. This allows
@@ -251,7 +179,7 @@ static int32_t computeRPNExpr(struct Patch const *patch,
popRPN();
value = INT32_MAX;
} else {
value = divide(popRPN(), value);
value = op_divide(popRPN(), value);
}
break;
case RPN_MOD:
@@ -263,7 +191,7 @@ static int32_t computeRPNExpr(struct Patch const *patch,
popRPN();
value = 0;
} else {
value = modulo(popRPN(), value);
value = op_modulo(popRPN(), value);
}
break;
case RPN_UNSUB:
@@ -278,7 +206,7 @@ static int32_t computeRPNExpr(struct Patch const *patch,
popRPN();
value = 0;
} else {
value = exponent(popRPN(), value);
value = op_exponent(popRPN(), value);
}
break;
@@ -332,11 +260,11 @@ static int32_t computeRPNExpr(struct Patch const *patch,
case RPN_SHL:
value = popRPN();
value = asl(popRPN(), value);
value = op_shift_left(popRPN(), value);
break;
case RPN_SHR:
value = popRPN();
value = asr(popRPN(), value);
value = op_shift_right(popRPN(), value);
break;
case RPN_BANK_SYM:

88
src/opmath.c Normal file
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@@ -0,0 +1,88 @@
/*
* This file is part of RGBDS.
*
* Copyright (c) 1997-2021, RGBDS contributors.
*
* SPDX-License-Identifier: MIT
*/
/*
* Mathematical operators that don't reuse C's behavior
*/
#include <stdint.h>
#include "opmath.h"
int32_t op_divide(int32_t dividend, int32_t divisor)
{
// Adjust division to floor toward negative infinity,
// not truncate toward zero
return dividend / divisor - ((dividend % divisor < 0) != (divisor < 0));
}
int32_t op_modulo(int32_t dividend, int32_t divisor)
{
int32_t remainder = dividend % divisor;
// Adjust modulo to have the sign of the divisor,
// not the sign of the dividend
return remainder + divisor * ((remainder < 0) != (divisor < 0));
}
int32_t op_exponent(int32_t base, uint32_t power)
{
int32_t result = 1;
for (;;) {
if (power % 2)
result *= base;
power /= 2;
if (!power)
break;
base *= base;
}
return result;
}
int32_t op_shift_left(int32_t value, int32_t amount)
{
// Get the easy cases out of the way
if (amount == 0)
return value;
if (value == 0 || amount >= 32)
return 0;
if (amount < -31)
return (value < 0) ? -1 : 0;
if (amount < 0)
return op_shift_right(value, -amount);
// Use unsigned to force a bitwise shift
// Casting back is OK because the types implement two's complement behavior
return (uint32_t)value << amount;
}
int32_t op_shift_right(int32_t value, int32_t amount)
{
// Repeat the easy cases here to avoid INT_MIN funny business
if (amount == 0)
return value;
if (value == 0 || amount <= -32)
return 0;
if (amount > 31)
return (value < 0) ? -1 : 0;
if (amount < 0)
return op_shift_left(value, -amount);
if (value > 0)
return (uint32_t)value >> amount;
// Calculate an OR mask for sign extension
// 1->0x80000000, 2->0xC0000000, ..., 31->0xFFFFFFFE
uint32_t amount_high_bits = -(UINT32_C(1) << (32 - amount));
// The C standard leaves shifting right negative values
// undefined, so use a left shift manually sign-extended
return ((uint32_t)value >> amount) | amount_high_bits;
}

32
test/asm/shift.err
View File

@@ -12,49 +12,41 @@ warning: shift.asm(16) -> shift.asm::test(6): [-Wshift-amount]
Shifting left by large amount 32
warning: shift.asm(17) -> shift.asm::test(3): [-Wshift-amount]
Shifting left by negative amount -9001
warning: shift.asm(17) -> shift.asm::test(3): [-Wshift-amount]
Shifting right by large amount 9001
warning: shift.asm(17) -> shift.asm::test(6): [-Wshift-amount]
Shifting left by negative amount -9001
warning: shift.asm(17) -> shift.asm::test(6): [-Wshift-amount]
Shifting right by large amount 9001
warning: shift.asm(19) -> shift.asm::test(3): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(19) -> shift.asm::test(6): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(20) -> shift.asm::test(3): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(20) -> shift.asm::test(3): [-Wshift-amount]
Shifting right by large amount 32
warning: shift.asm(20) -> shift.asm::test(6): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(20) -> shift.asm::test(6): [-Wshift-amount]
Shifting right by large amount 32
warning: shift.asm(21) -> shift.asm::test(3): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(21) -> shift.asm::test(3): [-Wshift-amount]
Shifting right by large amount 9001
warning: shift.asm(21) -> shift.asm::test(6): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(21) -> shift.asm::test(6): [-Wshift-amount]
Shifting right by large amount 9001
warning: shift.asm(22) -> shift.asm::test(3): [-Wshift]
Shifting negative value -4
Shifting right negative value -4
warning: shift.asm(22) -> shift.asm::test(6): [-Wshift]
Shifting negative value -4
Shifting right negative value -4
warning: shift.asm(23) -> shift.asm::test(3): [-Wshift]
Shifting negative value -4
Shifting right negative value -4
warning: shift.asm(23) -> shift.asm::test(6): [-Wshift]
Shifting negative value -4
Shifting right negative value -4
warning: shift.asm(24) -> shift.asm::test(3): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(24) -> shift.asm::test(3): [-Wshift-amount]
Shifting right by negative amount -9001
warning: shift.asm(24) -> shift.asm::test(3): [-Wshift-amount]
Shifting left by large amount 9001
warning: shift.asm(24) -> shift.asm::test(6): [-Wshift]
Shifting negative value -1
Shifting right negative value -1
warning: shift.asm(24) -> shift.asm::test(6): [-Wshift-amount]
Shifting right by negative amount -9001
warning: shift.asm(24) -> shift.asm::test(6): [-Wshift-amount]
Shifting left by large amount 9001