diff --git a/fuzzers/015-clbnffmux/.gitignore b/fuzzers/015-clbnffmux/.gitignore
index 93b5bef8..378eac25 100644
--- a/fuzzers/015-clbnffmux/.gitignore
+++ b/fuzzers/015-clbnffmux/.gitignore
@@ -1,4 +1 @@
-/specimen_*/
-/*.segbits
-/vivado.log
-/vivado.jou
+build
diff --git a/fuzzers/015-clbnffmux/Makefile b/fuzzers/015-clbnffmux/Makefile
index 8c74d1ae..f5f5a631 100644
--- a/fuzzers/015-clbnffmux/Makefile
+++ b/fuzzers/015-clbnffmux/Makefile
@@ -1,29 +1,3 @@
 N := 1
-SPECIMENS := $(addprefix specimen_,$(shell seq -f '%03.0f' $(N)))
-SPECIMENS_OK := $(addsuffix /OK,$(SPECIMENS))
-
-database: $(SPECIMENS_OK)
-	${XRAY_SEGMATCH} -o seg_clblx.segbits $(addsuffix /segdata_clbl[lm]_[lr].txt,$(SPECIMENS))
-
-pushdb:
-	${XRAY_MERGEDB} clbll_l seg_clblx.segbits
-	${XRAY_MERGEDB} clbll_r seg_clblx.segbits
-	${XRAY_MERGEDB} clblm_l seg_clblx.segbits
-	${XRAY_MERGEDB} clblm_r seg_clblx.segbits
-	${XRAY_DBFIXUP} --clb-int
-
-$(SPECIMENS_OK):
-	bash generate.sh $(subst /OK,,$@)
-	touch $@
-
-run:
-	$(MAKE) clean
-	$(MAKE) database
-	$(MAKE) pushdb
-	touch run.ok
-
-clean:
-	rm -rf specimen_[0-9][0-9][0-9]/ seg_clblx.segbits vivado*.log vivado_*.str vivado*.jou design *.bits *.dcp *.bit top.v run.ok
-
-.PHONY: database pushdb run clean
+include ../clb.mk
 
diff --git a/fuzzers/015-clbnffmux/generate.sh b/fuzzers/015-clbnffmux/generate.sh
index 8bfd1d47..50e0e763 100644
--- a/fuzzers/015-clbnffmux/generate.sh
+++ b/fuzzers/015-clbnffmux/generate.sh
@@ -2,18 +2,5 @@
 
 set -ex
 if [ $(vivado -h |grep Vivado |cut -d\  -f 2) != "v2017.2" ] ; then echo "FIXME: requires Vivado 2017.2. See https://github.com/SymbiFlow/prjxray/issues/14"; exit 1; fi
-
-source ${XRAY_GENHEADER}
-
-#echo '`define SEED 32'"'h$(echo $1 | md5sum | cut -c1-8)" > setseed.vh
-
-python3 ../top.py >top.v
-vivado -mode batch -source ../generate.tcl
-test -z "$(fgrep CRITICAL vivado.log)"
-
-for x in design*.bit; do
-	${XRAY_BITREAD} -F $XRAY_ROI_FRAMES -o ${x}s -z -y $x
-done
-
-python3 ../generate.py
+source ${XRAY_DIR}/utils/top_generate.sh
 
diff --git a/fuzzers/016-clbnoutmux/.gitignore b/fuzzers/016-clbnoutmux/.gitignore
index 826eddb4..9ef96044 100644
--- a/fuzzers/016-clbnoutmux/.gitignore
+++ b/fuzzers/016-clbnoutmux/.gitignore
@@ -1,5 +1,2 @@
-/specimen_*/
-/*.segbits
-!/o6.segbits
-/vivado.log
-/vivado.jou
+build
+
diff --git a/fuzzers/016-clbnoutmux/Makefile b/fuzzers/016-clbnoutmux/Makefile
index edc58e2e..f5f5a631 100644
--- a/fuzzers/016-clbnoutmux/Makefile
+++ b/fuzzers/016-clbnoutmux/Makefile
@@ -1,29 +1,3 @@
 N := 1
-SPECIMENS := $(addprefix specimen_,$(shell seq -f '%03.0f' $(N)))
-SPECIMENS_OK := $(addsuffix /OK,$(SPECIMENS))
-
-database: $(SPECIMENS_OK)
-	${XRAY_SEGMATCH} -o seg_clblx.segbits $(addsuffix /segdata_clbl[lm]_[lr].txt,$(SPECIMENS))
-
-pushdb:
-	${XRAY_MERGEDB} clbll_l seg_clblx.segbits
-	${XRAY_MERGEDB} clbll_r seg_clblx.segbits
-	${XRAY_MERGEDB} clblm_l seg_clblx.segbits
-	${XRAY_MERGEDB} clblm_r seg_clblx.segbits
-	${XRAY_DBFIXUP} --clb-int
-
-$(SPECIMENS_OK):
-	bash generate.sh $(subst /OK,,$@)
-	touch $@
-
-run:
-	$(MAKE) clean
-	$(MAKE) database
-	$(MAKE) pushdb
-	touch run.ok
-
-clean:
-	rm -rf specimen_[0-9][0-9][0-9]/ *.segbits vivado*.log vivado_*.str vivado*.jou design *.bits *.dcp *.bit top.v run.ok
-
-.PHONY: database pushdb run clean
+include ../clb.mk
 
diff --git a/fuzzers/016-clbnoutmux/generate.sh b/fuzzers/016-clbnoutmux/generate.sh
index 8bfd1d47..50e0e763 100644
--- a/fuzzers/016-clbnoutmux/generate.sh
+++ b/fuzzers/016-clbnoutmux/generate.sh
@@ -2,18 +2,5 @@
 
 set -ex
 if [ $(vivado -h |grep Vivado |cut -d\  -f 2) != "v2017.2" ] ; then echo "FIXME: requires Vivado 2017.2. See https://github.com/SymbiFlow/prjxray/issues/14"; exit 1; fi
-
-source ${XRAY_GENHEADER}
-
-#echo '`define SEED 32'"'h$(echo $1 | md5sum | cut -c1-8)" > setseed.vh
-
-python3 ../top.py >top.v
-vivado -mode batch -source ../generate.tcl
-test -z "$(fgrep CRITICAL vivado.log)"
-
-for x in design*.bit; do
-	${XRAY_BITREAD} -F $XRAY_ROI_FRAMES -o ${x}s -z -y $x
-done
-
-python3 ../generate.py
+source ${XRAY_DIR}/utils/top_generate.sh
 
diff --git a/fuzzers/017-clbprecyinit/.gitignore b/fuzzers/017-clbprecyinit/.gitignore
index 93a7f16a..9ef96044 100644
--- a/fuzzers/017-clbprecyinit/.gitignore
+++ b/fuzzers/017-clbprecyinit/.gitignore
@@ -1,5 +1,2 @@
-/specimen_*/
-/*.segbits
-/vivado.log
-/vivado.jou
-/run.ok
+build
+
diff --git a/fuzzers/017-clbprecyinit/Makefile b/fuzzers/017-clbprecyinit/Makefile
index 8c74d1ae..f5f5a631 100644
--- a/fuzzers/017-clbprecyinit/Makefile
+++ b/fuzzers/017-clbprecyinit/Makefile
@@ -1,29 +1,3 @@
 N := 1
-SPECIMENS := $(addprefix specimen_,$(shell seq -f '%03.0f' $(N)))
-SPECIMENS_OK := $(addsuffix /OK,$(SPECIMENS))
-
-database: $(SPECIMENS_OK)
-	${XRAY_SEGMATCH} -o seg_clblx.segbits $(addsuffix /segdata_clbl[lm]_[lr].txt,$(SPECIMENS))
-
-pushdb:
-	${XRAY_MERGEDB} clbll_l seg_clblx.segbits
-	${XRAY_MERGEDB} clbll_r seg_clblx.segbits
-	${XRAY_MERGEDB} clblm_l seg_clblx.segbits
-	${XRAY_MERGEDB} clblm_r seg_clblx.segbits
-	${XRAY_DBFIXUP} --clb-int
-
-$(SPECIMENS_OK):
-	bash generate.sh $(subst /OK,,$@)
-	touch $@
-
-run:
-	$(MAKE) clean
-	$(MAKE) database
-	$(MAKE) pushdb
-	touch run.ok
-
-clean:
-	rm -rf specimen_[0-9][0-9][0-9]/ seg_clblx.segbits vivado*.log vivado_*.str vivado*.jou design *.bits *.dcp *.bit top.v run.ok
-
-.PHONY: database pushdb run clean
+include ../clb.mk
 
diff --git a/fuzzers/017-clbprecyinit/generate.sh b/fuzzers/017-clbprecyinit/generate.sh
index 54774bf8..f42f840c 100644
--- a/fuzzers/017-clbprecyinit/generate.sh
+++ b/fuzzers/017-clbprecyinit/generate.sh
@@ -1,18 +1,5 @@
 #!/bin/bash
 
 set -ex
-
-source ${XRAY_GENHEADER}
-
-#echo '`define SEED 32'"'h$(echo $1 | md5sum | cut -c1-8)" > setseed.vh
-
-python3 ../top.py >top.v
-vivado -mode batch -source ../generate.tcl
-test -z "$(fgrep CRITICAL vivado.log)"
-
-for x in design*.bit; do
-	${XRAY_BITREAD} -F $XRAY_ROI_FRAMES -o ${x}s -z -y $x
-done
-
-python3 ../generate.py
+source ${XRAY_DIR}/utils/top_generate.sh
 
diff --git a/fuzzers/025-bram-config/Makefile b/fuzzers/025-bram-config/Makefile
index 01b733c4..46c9ba13 100644
--- a/fuzzers/025-bram-config/Makefile
+++ b/fuzzers/025-bram-config/Makefile
@@ -14,7 +14,7 @@ build:
 	mkdir build
 
 $(SPECIMENS_OK): build
-	bash generate.sh $(subst /OK,,$@)
+	bash ${XRAY_DIR}/utils/top_generate.sh $(subst /OK,,$@)
 	touch $@
 
 run:
diff --git a/fuzzers/050-intpips/Makefile b/fuzzers/050-intpips/Makefile
index 2570d491..4bc41c16 100644
--- a/fuzzers/050-intpips/Makefile
+++ b/fuzzers/050-intpips/Makefile
@@ -12,13 +12,13 @@ database: $(SPECIMENS_OK)
 	${XRAY_MASKMERGE} mask_clblm_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
 	${XRAY_MERGEDB} mask_clbll_l mask_clbll_l.segbits
 	${XRAY_MERGEDB} mask_clbll_r mask_clbll_r.segbits
 	${XRAY_MERGEDB} mask_clblm_l mask_clblm_l.segbits
 	${XRAY_MERGEDB} mask_clblm_r mask_clblm_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK):
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/051-imuxlout/Makefile b/fuzzers/051-imuxlout/Makefile
index a2704db4..46a1e5e8 100644
--- a/fuzzers/051-imuxlout/Makefile
+++ b/fuzzers/051-imuxlout/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -m 5 -M 15 -o seg_int_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK): todo.txt
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/052-clkin/Makefile b/fuzzers/052-clkin/Makefile
index 848e0de4..12edecb2 100644
--- a/fuzzers/052-clkin/Makefile
+++ b/fuzzers/052-clkin/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -m 5 -M 15 -o seg_int_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK): todo.txt
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/053-ctrlin/Makefile b/fuzzers/053-ctrlin/Makefile
index 848e0de4..12edecb2 100644
--- a/fuzzers/053-ctrlin/Makefile
+++ b/fuzzers/053-ctrlin/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -m 5 -M 15 -o seg_int_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK): todo.txt
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/054-gfan/Makefile b/fuzzers/054-gfan/Makefile
index 848e0de4..12edecb2 100644
--- a/fuzzers/054-gfan/Makefile
+++ b/fuzzers/054-gfan/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -m 5 -M 15 -o seg_int_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK): todo.txt
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/055-gnd/Makefile b/fuzzers/055-gnd/Makefile
index 611626f7..e92d2497 100644
--- a/fuzzers/055-gnd/Makefile
+++ b/fuzzers/055-gnd/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -m 5 -M 15 -o seg_int_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK): todo.txt
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/056-rempips/Makefile b/fuzzers/056-rempips/Makefile
index daf82238..ccf3ceb4 100644
--- a/fuzzers/056-rempips/Makefile
+++ b/fuzzers/056-rempips/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -m 5 -M 15 -o seg_int_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK): todo.txt
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/057-bipips/Makefile b/fuzzers/057-bipips/Makefile
index e5fd419b..7c2d5ad1 100644
--- a/fuzzers/057-bipips/Makefile
+++ b/fuzzers/057-bipips/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -m 5 -M 15 -o seg_int_r.segbits $(addsuffix /segdata_int_r.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} int_l seg_int_l.segbits
 	${XRAY_MERGEDB} int_r seg_int_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK): todo.txt
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/058-hclkpips/Makefile b/fuzzers/058-hclkpips/Makefile
index 59cdcdd5..09f8b019 100644
--- a/fuzzers/058-hclkpips/Makefile
+++ b/fuzzers/058-hclkpips/Makefile
@@ -12,13 +12,13 @@ database: $(SPECIMENS_OK)
 	grep CK_INOUT seg_hclk_r.segbits | sed 's, .*, always,' > ppips_hclk_r.txt
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} hclk_l seg_hclk_l.segbits
 	${XRAY_MERGEDB} hclk_r seg_hclk_r.segbits
 	${XRAY_MERGEDB} mask_hclk_l mask_hclk_l.segbits
 	${XRAY_MERGEDB} mask_hclk_r mask_hclk_r.segbits
 	cp ppips_hclk_l.txt  ${XRAY_DATABASE_DIR}/$(XRAY_DATABASE)/ppips_hclk_l.db
 	cp ppips_hclk_r.txt  ${XRAY_DATABASE_DIR}/$(XRAY_DATABASE)/ppips_hclk_r.db
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK):
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/100-dsp-mskpat/Makefile b/fuzzers/100-dsp-mskpat/Makefile
index 18c24803..c4d099c6 100644
--- a/fuzzers/100-dsp-mskpat/Makefile
+++ b/fuzzers/100-dsp-mskpat/Makefile
@@ -8,9 +8,9 @@ database: $(SPECIMENS_OK)
 	${XRAY_SEGMATCH} -o seg_dsp_r.segbits $(addsuffix /segdata_dsp_r_*.txt,$(SPECIMENS))
 
 pushdb:
+	${XRAY_DBFIXUP} --db-dir . --clb-int
 	${XRAY_MERGEDB} dsp_l seg_dsp_l.segbits
 	${XRAY_MERGEDB} dsp_r seg_dsp_r.segbits
-	${XRAY_DBFIXUP} --clb-int
 
 $(SPECIMENS_OK):
 	bash generate.sh $(subst /OK,,$@)
diff --git a/fuzzers/clb.mk b/fuzzers/clb.mk
new file mode 100644
index 00000000..dd8f6d0d
--- /dev/null
+++ b/fuzzers/clb.mk
@@ -0,0 +1,32 @@
+N := 1
+SPECIMENS := $(addprefix build/specimen_,$(shell seq -f '%03.0f' $(N)))
+SPECIMENS_OK := $(addsuffix /OK,$(SPECIMENS))
+
+database: $(SPECIMENS_OK)
+	${XRAY_SEGMATCH} -o build/seg_clblx.segbits $(addsuffix /segdata_clbl[lm]_[lr].txt,$(SPECIMENS))
+
+pushdb:
+	${XRAY_DBFIXUP} --db-dir build --clb-int
+	${XRAY_MERGEDB} clbll_l build/seg_clblx.segbits
+	${XRAY_MERGEDB} clbll_r build/seg_clblx.segbits
+	${XRAY_MERGEDB} clblm_l build/seg_clblx.segbits
+	${XRAY_MERGEDB} clblm_r build/seg_clblx.segbits
+
+build:
+	mkdir build
+
+$(SPECIMENS_OK): build
+	bash generate.sh $(subst /OK,,$@)
+	touch $@
+
+run:
+	$(MAKE) clean
+	$(MAKE) database
+	$(MAKE) pushdb
+	touch run.ok
+
+clean:
+	rm -rf build
+
+.PHONY: database pushdb run clean
+
diff --git a/fuzzers/025-bram-config/generate.sh b/utils/top_generate.sh
similarity index 71%
rename from fuzzers/025-bram-config/generate.sh
rename to utils/top_generate.sh
index abebd98c..f07384aa 100644
--- a/fuzzers/025-bram-config/generate.sh
+++ b/utils/top_generate.sh
@@ -1,11 +1,12 @@
 #!/bin/bash
+# Generic generate.sh for scripts that use top.py to generate top.v
+# and then use generate.py for segment generation
 
 set -ex
 
 FUZDIR=$PWD
 source ${XRAY_GENHEADER}
 
-
 python3 $FUZDIR/top.py >top.v
 vivado -mode batch -source $FUZDIR/generate.tcl
 test -z "$(fgrep CRITICAL vivado.log)"