- Smaller C: fix a bug in __func__ introduced with
float-related changes
- make *printf() print floats greater than 1e25
- make *printf() print the plus sign when the format
includes "+", e.g. printf("%+f\n", 1.0);
- clean up and complete prototypes in <math.h>
- remove non-standard HUGE and LOGHUGE from <math.h>
- add HUGE_VAL to <math.h>
- express some hard-coded limits in terms of constants
from <float.h>
- uncomment prototypes of several floating point
conversion functions in <stdlib.h> for Smaller C
double is an alias for float. IOW, only 32-bit
single precision floats are supported. This isn't
conformant, but OK for some embedded systems (e.g.
RetroBSD) and simple compilers like this.
Also, the following operators are not supported with
floats at the moment: ++, --, +=, -=, *=, /=.
But +, -, *, /, =, ||, &&, ?:, !, comparison, casts,
if/while/for are OK.
Also:
- A few bugfixes in virtualmips
- Compile Smaller C (smlrc) using MIPS16e
(this frees up ~20KB of space for smlrc improvements)
TBD:
- MIPS16e disassembler in virtualmips
All architectures:
- "return" statement at function's end doesn't jump to immediately
following epilog anymore
- zero and non-zero constants are recognized in conditional
expressions of "if", "do/while" and "for" statements, no code
generated to evaluate these constant conditions and related
unnecessary jumps aren't generated anymore either
- in "for (clause-1; expr-2; expr-3) body", "expr-3" and "body" are
now reordered to the more natural code flow "body expr-3", thereby
getting rid of unnecessary jumps
MIPS code generator:
- function prologue/epilogue shortened further
- RA is not explicitly saved/restored in leaf functions
- assignment of 0 (e.g. "int a = 0;") is done from register 0
directly, avoiding a load of a constant
- Update license text (remove irrelevant FreeBSD references)
- Update root readme.txt
- Improve prologue/epilogue generation
Don't generate unnecessary jumps back and forth to/from
"sub sp, size_of_locals".
Instead, with the help of fgetpos()/fsetpos()
initially write ";sub sp, 0" and then, when
the size is finally known, go back and overwrite it with
" sub sp, size_of_locals".
- type specifiers may occur in any order
(e.g. "unsigned short int" and "int short unsigned")
- use .rodata/.rdata section for string literals
- arbitrary length string literals (hooray!)
- better concatenation of adjacent string literals
(now works even across preprocessor directives)
Support .bss section
- -nobss option in smlrc: use .data instead of .bss as before
- take advantage of .bss in smlrc (put a large array into it)
Remove dead/useless code
Remove useless/rarely used features/options:
-use-gp (MIPS)
-flat16/-flat32 (x86)
-seg16t (x86), -seg16 is now the default
-ctor-fxn
Add/change:
- use EXIT_FAILURE=1 instead of -1 in smlrc when aborting
due to an error
- properly sign-/zero-extend returned values, e.g. the following
function must return 255 and not -1:
unsigned char f(void) { return -1; }
- properly decay arrays on the left side of ->, e.g. the following must
compile:
{
struct {char c;} s[1];
s[0].c = 'a'; putchar(s[0].c);
(s+0)->c = 'b'; putchar(s[0].c);
(*s).c = 'c'; putchar(s[0].c);
s->c = 'd'; putchar(s[0].c);
putchar('\n');
}
Also:
- support structure passing/returning by value (x86 only)
Improvements:
- use registers more efficiently
- eliminate some register copies and stack manipulations
- promote left operands to right immediate operands
- improve simple assignments to auto/static vars
- use bltz, blez, bgtz, bgez
- change mul/divu (by powers of 2) to sll/srl/and
- use seb, seh for sign extension instead of sll/sra
- overall generate a bit tighter, faster and more readable asm code
Fixes:
- >>= should be unsigned when the left operand is unsigned int.
The right operand isn't important here.
- very subtle bug in e.g. void f(){int a; &a+1;/*wrong value of &a+1*/}
Other:
- include stdarg.c and skeleton.c in /share/example/Makefile
- move va_list type detection under #ifdef as it's rarely needed anyway
- allow up to 254 characters in a string literal
- generate a warning when an integer is passed instead of a pointer (and
vice versa) as a function parameter (pass -Wall for this)
- when printing an unexpected token, print identifier tokens instead of
'<tokIdent>'
- fix: allow most control characters inside '' and ""
- fix handling of -I<path> and -SI<path>
- switch() now supports Duff's device
- for() now supports declarations in its first clause as in C99/C++
Fixes/workarounds:
- octal escape sequence is to be terminated no later than after three
octal digits:
"\1011" is now parsed equivalently to "A1"
- workaround truncation of immediate operands to 16 bits in MIPS
instructions addi[u], subi[u], slti[u], andi, ori, xori in RetroBSD's as
(disabled since as is being fixed).
Improvements:
- warn on string literal truncation when initializing array of char
- generate trap/break-less form of MIPS div[u]
New:
- experimental support for __interrupt functions (x86/huge only)
Fixed bug in C preprocessor: buffer size reduced to avoid allocation failure.
Added option -v for smlrc.
New example stdarg.c: a demo of function with variable arguments.
The following global/static pointer initialization should now work:
static char* p1 = "abc" + 1;
static char* p2 = "abc" - 1;
static char* p3 = 1 + "abc";
static int a333[3][3][3];
static int* pa333_111 = &a333[1][1][1];
Other seemingly (and in fact actually) functionality preserving changes
are only to reduce code size when self compiling for DOS using -seg16.
Improvements and fixes require space, sigh.
In the following
typedef struct S0 { char ac[4]; } T1;
int v26 = (int)&((T1*)0)->ac[3];
int v27 = &((T1*)0)->ac[3];
v27 should be initialized to 3 just as v26.
Improvements:
- support initialization of multidimensional arrays
- support initialization of structures
- support initialization of structures and arrays inside functions
- support static inside functions
Notes:
- Only fully-bracketed (sic) initialization of arrays is supported.
- && and || have been partially replaced with & and | to slightly reduce
code size when self compiling for DOS using -seg16.
