diff --git a/.gitignore b/.gitignore
index fc591e2..569dcc0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -219,3 +219,4 @@ __marimo__/
 
 alt-rpm
 set.c
+rpm-build
diff --git a/usage_setc_rpm.md b/usage_setc_rpm.md
new file mode 100644
index 0000000..fe78bf4
--- /dev/null
+++ b/usage_setc_rpm.md
@@ -0,0 +1,80 @@
+rg rpmsetcmp:
+
+```
+tools/setcmp.c
+12-{
+13: int cmp = rpmsetcmp(s1, s2);
+14- switch (cmp) {
+
+alt/rpm.spec
+709-_ Mon Nov 25 2019 Andrew Savchenko <bircoph@altlinux.org> 4.13.0.1-alt15
+710:- Support rpmsetcmp profiling on E2K.
+711-
+--
+713-- Added triggers circumvention for packagekit offline update (by Aleksei Nikiforov).
+714:- Imported rpmsetcmp optimization from rpm-build.
+715-
+--
+1094-- set.c: Increased cache size from 160 to 256 slots, 75 percent hit ratio.
+1095:- set.c: Implemented 4-byte and 8-byte steppers for rpmsetcmp main loop.
+1096-
+--
+1314-_ Mon Sep 20 2010 Alexey Tourbin <at@altlinux.ru> 4.0.4-alt98.47
+1315:- set.c (rpmsetcmp): Fixed check for set2 decoding error.
+1316-- brp-cleanup: Updated for /usr/lib64/perl5 and /usr/share/perl5.
+
+lib/rpmds.c
+1087- if (aset && bset) {
+1088: sense = rpmsetcmp(AEVR, BEVR);
+1089- if (sense < -1) {
+
+---
+
+rg set_new:
+none
+
+---
+
+rg set_add
+none
+
+---
+
+rg set_fini:
+none
+
+---
+
+rg set_free:
+none
+```
+
+---
+
+rg setcmp:
+
+```
+Makefile.am
+218-
+219:noinst_PROGRAMS = setcmp
+220:setcmp_SOURCES = tools/setcmp.c
+221:setcmp_LDADD = lib/librpm.la
+222-
+
+alt/rpm.spec
+311-rpmquery -a --requires |fgrep '= set:' |sort >R
+312:join -o 1.3,2.3 P R |shuf >setcmp-data
+313:time ./setcmp <setcmp-data >/dev/null
+314-rm lib/set.lo lib/librpm.la
+--
+318-%if_with profile
+319:time ./setcmp <setcmp-data >/dev/null
+320-rm lib/set.lo lib/librpm.la
+321-%make_build -C lib set.lo librpm.la CFLAGS="$set_c_cflags -fprofile-generate"
+322:./setcmp <setcmp-data >/dev/null
+323-%ifnarch %e2k
+--
+332-%make_build
+333:time ./setcmp <setcmp-data >/dev/null
+334-
+```
diff --git a/usage_setc_rpm_build.md b/usage_setc_rpm_build.md
new file mode 100644
index 0000000..77eb83b
--- /dev/null
+++ b/usage_setc_rpm_build.md
@@ -0,0 +1,99 @@
+rg rpmsetcmp:
+
+```
+tools/setcmp.c
+12-{
+13:    int cmp = rpmsetcmp(s1, s2);
+14-    switch (cmp) {
+
+lib/depends.c
+124-    if (aset && bset) {
+125:	sense = rpmsetcmp(AEVR, BEVR);
+126-	if (sense < -1) {
+
+rpm-4_0.spec
+1231-- set.c: Increased cache size from 160 to 256 slots, 75 percent hit ratio.
+1232:- set.c: Implemented 4-byte and 8-byte steppers for rpmsetcmp main loop.
+1233-
+--
+1451-* Mon Sep 20 2010 Alexey Tourbin <at@altlinux.ru> 4.0.4-alt98.47
+1452:- set.c (rpmsetcmp): Fixed check for set2 decoding error.
+1453-- brp-cleanup: Updated for /usr/lib64/perl5 and /usr/share/perl5.
+
+build/reqprov.c
+175-	if (aset && bset) {
+176:	   sense = rpmsetcmp(Aevr, Bevr);
+177-	   if (sense < -1)
+```
+
+---
+
+rg set_new:
+
+```
+tools/mkset.c
+11-    assert(bpp <= 32);
+12:    struct set *set = set_new();
+13-    char *line = NULL;
+```
+
+---
+
+rg set_add:
+
+```
+tools/mkset.c
+21-	   continue;
+22:	set_add(set, line);
+23-	added++;
+```
+
+---
+
+rg set_fini:
+
+```
+tools/mkset.c
+25-    assert(added > 0);
+26:    const char *str = set_fini(set, bpp);
+27-    assert(str);
+```
+
+---
+
+rg set_free:
+none
+
+---
+
+rg mkset:
+
+```
+rpm-4_0.spec
+431-# set-version helpers
+432:%rpmattr %_rpmlibdir/mkset
+433-%rpmattr %_rpmlibdir/setcmp
+--
+1458-- rpmlibprov.c: Added rpmlib(SetVersions) feature.
+1459:- %_rpmlibdir/mkset: Command-line helper for making set-versions.
+1460-- lib.prov: Implemented soname set-versioning with exported symbols.
+
+tools/Makefile.am
+37-	relative \
+38:	mkset \
+39-	setcmp \
+--
+62-
+63:mkset_SOURCES = mkset.c
+64-setcmp_SOURCES = setcmp.c
+
+autodeps/lib.prov.in
+112-		Info "$f: $n symbols, $bpp bpp"
+113:		set=$(printf '%s\n' "$sym" |"${RPMB_TOOLS_DIR-@RPMCONFIGDIR@}/mkset" "$bpp")
+114-		printf '%s = %s\n' "$provname" "$set"
+
+autodeps/lib.req.in
+306-	#printf '%s\n' "$reqsym" |LC_ALL=C sort -c -u
+307:	set=$(printf '%s\n' "$reqsym" |"${RPMB_TOOLS_DIR-@RPMCONFIGDIR@}/mkset" "$bpp")
+308-	printf '%s >= %s\n' "$dep" "$set"
+```