Most of the programs showed here are inspired by the book Hacker's Delight. While reading it, I start wondering if there wasn't a possibiity to create branch-free routines for date and time routines. The goal is to create routines that I could use on XMM, SSE etc... one routine for lots of data. Allthough easy in their coding, there weren't always easy to find and I even don't have a mathematic proof for them. It was trying, observing, re-trying and so one until I got for all data applicable the right solution. Lucky me there are just 12 months in a year. The routines for sleep and leapyear do have branches, which for leapyear I still am looking for another solution.

There are no libraries required, even better a static or shared library perhaps could be useful. All files are build with following makefile.
Downloading the source code can be done here on Github.

BIN=daysinmonth leapyear trimester quadrimester semester shiftedmonth sleep
NASM=/usr/bin/nasm
NASMOPTS=-felf64
NASMDBG=-Fdwarf

.PHONY: all clean

all: $(BIN)

clean:
	rm -rf $(BIN).o $(BIN).dev.o $(BIN)

%: %.asm %.c
	$(NASM) $(NASMOPTS) -o $@.o $<
	$(NASM) $(NASMOPTS) $(NASMDBG) -o $@.dev.o $<
	$(CC) -o $@ $@.c $@.o