Philipp Krause

SDCC 3.7.0 Released

Discussion created by Philipp Krause on Feb 26, 2018

Today, SDCC 3.7.0 has been released. As always it has been put online in the SourceForge File section.


Since we are having some troubles with some machines in our compile farm, for 3.7.0 no binaries are released. The release consists of source and documentation tarballs only. Also, Maarten, who has been the release manager for a few years, is currently too busy to manage the 3.7.0 release. We hope to be back to normal for a 3.8.0 release later this year.


There have been a lot of improvements, both features and bug fixes since SDCC 3.6.0. The full ChangeLog is at: 


The following is a list of particularly noticeable new features.


  • Changed putchar() prototype from void putchar(char) to int putchar(int) to improve standard-compliance and allow error reporting.
  • Various speed improvements in stm8 backend - Dhrystone score more than doubled, resulting in SDCC achieving the highest Dhrystone scores among STM8 C implementations.
  • Various speed improvements for multiplications resulting in SDCC achieving the highest Coremark scores among STM8 C implementations.
  • Declarations in for loops (ISO C99).
  • 64-bit integers (long long) for the mcs51 and ds390 backends (now long long is fully supported in SDCC except for the pic14 and pic16 backends).
  • Full _Bool support for mcs51 and ds390 backend (now _Bool is fully supported in SDCC regardless of backend).
  • Additional wide character library functions: mbstowcs() and wcstombs(), btowc() and wctob(), wcscmp(), wcslen().
  • Changed PRNG for rand() from LCG to xorshift to improve speed and quality.
  • Support for Small-C calling convention on the callee side (i.e. function definitions with Small-C calling convention).
  • The obsolete macro SDCC (which used to contain the version number encoded as an integer) has finally been removed (except for mcs51, where it will survive a little bit longer for SiLabs IDE compability).
  • New devices supported by simulator (TLCS-90, and the 517, F380, XC88X, DS320 mcs51-variants along with dual-dptr and MDU support).
  • Timer, UART (incl. interrupt) and I/O support in STM8 simulator.
  • Simulator support for banked memory and bit banding.
  • Various simulator improvements: Conditional breakpoints, breakpoints by function name from SDCC debug output, OMF input, VCD output, simulator interface for simulated program and new operators in expressions.
  • Deprecated --nojtbound and the corresponding pragma.
  • Faster register allocator reduces compilation time by about 25% (does not apply to mcs51, ds390 which use a different register allocator).
  • Execution count guessing and use of execution count guesses in stm8 register allocation improve optimization for code speed.
  • Changed getchar() prototype from char getchar(void) to int getchar(void) to improve standard-compliance and allow error reporting.
  • Type qualifiers in array parameters (ISO C99).
  • static in array parameters (ISO C99).
  • Improved support for DWARFv2 debug info in ELF output (stm8, hc08, s08).
  • Various improvements in z80/z180/gbz80/tlcs90/r2k/r3ka code generation, in particular for mixed 16-/32-bit code.
  • __z88dk_fastcall function pointer support for --reserve-regs-iy.
  • tlcs90 is now a fully supported backend, no longer work in progress.
  • --data-seg to specify the segment for non-initialized data in the z80, z180, gbz80, tlcs90, r2k and r3ka backends.
  • New methods to obtain tree-decompositions of control-flow graphs improve compilation time / code-quality trade-off (when SDCC is built with support for the treedec library).
  • Additional general utility functions: qsort(), strtol(), strtoul().


Philipp Klaus Krause
SDCC 3.7.0 Release Manager