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Added range checking for addition, subtraction, negation and division in the occam support headers

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Neil Brown 2009-01-22 11:26:06 +00:00
parent 1b51eb5d63
commit fdeab43b3c
1 changed files with 42 additions and 14 deletions
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56
support/tock_support.h
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@ -83,7 +83,7 @@ static inline int occam_check_index (int i, int limit, const char *pos) {
static inline int occam_check_index_lower (int, const char *) occam_unused; static inline int occam_check_index_lower (int, const char *) occam_unused;
static inline int occam_check_index_lower (int i, const char *pos) { static inline int occam_check_index_lower (int i, const char *pos) {
if (i < 0) { if (i < 0) {
occam_stop (pos, 3, "invalid array index %d (should be 0 <= i)", i); occam_stop (pos, 2, "invalid array index %d (should be 0 <= i)", i);
} }
return i; return i;
} }
@ -112,21 +112,38 @@ static inline int occam_check_retype (int src, int dest, const char *pos) {
} \ } \
return n; \ return n; \
} }
// Some things taken from http://www.fefe.de/intof.html
#define __HALF_MAX_SIGNED(type) ((type)1 << (sizeof(type)*8-2))
#define __MAX_SIGNED(type) (__HALF_MAX_SIGNED(type) - 1 + __HALF_MAX_SIGNED(type))
#define __MIN_SIGNED(type) (-1 - __MAX_SIGNED(type))
#define __MIN(type) ((type)-1 < 1?__MIN_SIGNED(type):(type)0)
#define __MAX(type) ((type)~__MIN(type))
// FIXME All of these need to check for overflow and report errors appropriately. // FIXME All of these need to check for overflow and report errors appropriately.
#define MAKE_ADD(type) \ #define MAKE_ADD(type) \
static inline type occam_add_##type (type, type, const char *) occam_unused; \ static inline type occam_add_##type (type, type, const char *) occam_unused; \
static inline type occam_add_##type (type a, type b, const char *pos) { \ static inline type occam_add_##type (type a, type b, const char *pos) { \
return a + b; \ if (((b<1)&&(__MIN(type)-b<=a)) || ((b>=1)&&(__MAX(type)-b>=a))) {return a + b;} \
else { occam_stop(pos, 3, "integer overflow when doing %d + %d", a, b); return 0; } \
} }
#define MAKE_ADDF(type) \
static inline type occam_add_##type (type, type, const char *) occam_unused; \
static inline type occam_add_##type (type a, type b, const char *pos) { return a + b;}
#define MAKE_SUBTR(type) \ #define MAKE_SUBTR(type) \
static inline type occam_subtr_##type (type, type, const char *) occam_unused; \ static inline type occam_subtr_##type (type, type, const char *) occam_unused; \
static inline type occam_subtr_##type (type a, type b, const char *pos) { \ static inline type occam_subtr_##type (type a, type b, const char *pos) { \
return a - b; \ if (((b<1)&&(__MAX(type)+b>=a)) || ((b>=1)&&(__MIN(type)+b<=a))) {return a - b;} \
else { occam_stop(pos, 3, "integer overflow when doing %d - %d", a, b); } \
} }
#define MAKE_SUBTRF(type) \
static inline type occam_subtr_##type (type, type, const char *) occam_unused; \
static inline type occam_subtr_##type (type a, type b, const char *pos) { return a - b;}
#define MAKE_MUL(type) \ #define MAKE_MUL(type) \
static inline type occam_mul_##type (type, type, const char *) occam_unused; \ static inline type occam_mul_##type (type, type, const char *) occam_unused; \
static inline type occam_mul_##type (type a, type b, const char *pos) { \ static inline type occam_mul_##type (type a, type b, const char *pos) { \
return a * b; \ return a * b; /*TODO*/ \
} }
#define MAKE_DIV(type) \ #define MAKE_DIV(type) \
static inline type occam_div_##type (type, type, const char *) occam_unused; \ static inline type occam_div_##type (type, type, const char *) occam_unused; \
@ -134,13 +151,24 @@ static inline int occam_check_retype (int src, int dest, const char *pos) {
if (b == 0) { \ if (b == 0) { \
occam_stop (pos, 1, "divide by zero"); \ occam_stop (pos, 1, "divide by zero"); \
} \ } \
return a / b; \ else if (b == -1 && a == __MIN(type)) /* only overflow I can think of */ { \
occam_stop (pos, 1, "overflow in division"); \
} else { return a / b; } \
} }
#define MAKE_DIVF(type) \
static inline type occam_div_##type (type, type, const char *) occam_unused; \
static inline type occam_div_##type (type a, type b, const char *pos) { return a / b;}
#define MAKE_NEGATE(type) \ #define MAKE_NEGATE(type) \
static inline type occam_negate_##type (type, const char *) occam_unused; \ static inline type occam_negate_##type (type, const char *) occam_unused; \
static inline type occam_negate_##type (type a, const char *pos) { \ static inline type occam_negate_##type (type a, const char *pos) { \
return - a; \ if (a == __MIN(type)) { \
occam_stop (pos, 1, "overflow in negation"); \
} else {return - a;} \
} }
#define MAKE_NEGATEF(type) \
static inline type occam_negate_##type (type, const char *) occam_unused; \
static inline type occam_negate_##type (type a, const char *pos) { return - a; }
// occam's \ doesn't behave like C's %; it handles negative arguments. // occam's \ doesn't behave like C's %; it handles negative arguments.
// (Effectively it ignores signs coming in, and the output sign is the sign of // (Effectively it ignores signs coming in, and the output sign is the sign of
// the first argument.) // the first argument.)
@ -264,20 +292,20 @@ MAKE_ALL_SIGNED(int64_t, "%lld", uint64_t)
// FIXME range checks for float and double shouldn't work this way // FIXME range checks for float and double shouldn't work this way
//{{{ float //{{{ float
MAKE_RANGE_CHECK(float, "%f") MAKE_RANGE_CHECK(float, "%f")
MAKE_ADD(float) MAKE_ADDF(float)
MAKE_SUBTR(float) MAKE_SUBTRF(float)
MAKE_MUL(float) MAKE_MUL(float)
MAKE_DIV(float) MAKE_DIVF(float)
MAKE_NEGATE(float) MAKE_NEGATEF(float)
MAKE_DUMB_REM(float) MAKE_DUMB_REM(float)
//}}} //}}}
//{{{ double //{{{ double
MAKE_RANGE_CHECK(double, "%f") MAKE_RANGE_CHECK(double, "%f")
MAKE_ADD(double) MAKE_ADDF(double)
MAKE_SUBTR(double) MAKE_SUBTRF(double)
MAKE_MUL(double) MAKE_MUL(double)
MAKE_DIV(double) MAKE_DIVF(double)
MAKE_NEGATE(double) MAKE_NEGATEF(double)
MAKE_DUMB_REM(double) MAKE_DUMB_REM(double)
//}}} //}}}