gbdev/rgbds
1
0
Fork 0
mirror of https://github.com/gbdev/rgbds.git synced 2025-11-21 10:42:07 +00:00
Code Issues Packages Projects Releases Wiki Activity

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

Browse Source 
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
Download Patch File Download Diff File Expand all files Collapse all files

96
src/asm/rpn.c
View File

@@ -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: