Added FIR example

Makefile

@@ -9,7 +9,7 @@ install:
 	cp ${RISCV}/riscv-isa-sim/arch_test_target/spike/Makefile.include addins/riscv-arch-test/
 	sed -i '/export TARGETDIR ?=/c\export TARGETDIR ?= ${RISCV}/riscv-isa-sim/arch_test_target' addins/riscv-arch-test/Makefile.include
 	echo export RISCV_PREFIX = riscv64-unknown-elf- >> addins/riscv-arch-test/Makefile.include
-	tests/linux-testgen/linux-testvectors/tvLinker.sh
+	# tests/linux-testgen/linux-testvectors/tvLinker.sh # needs to be run in local directory
 
 regression:
 	make -C pipelined/regression

examples/C/fir/Makefile

@@ -0,0 +1,33 @@
+TARGET = fir
+
+$(TARGET).objdump: $(TARGET)
+	riscv64-unknown-elf-objdump -S -D $(TARGET) > $(TARGET).objdump
+	spike $(TARGET)
+    
+$(TARGET): $(TARGET).c Makefile
+	riscv64-unknown-elf-gcc -o $(TARGET) -g -O\
+	  -march=rv64gc -mabi=lp64d -mcmodel=medany \
+	  -nostdlib -static -lm -fno-tree-loop-distribute-patterns \
+	  -T../common/test.ld -I../common \
+	  $(TARGET).c ../common/crt.S ../common/syscalls.c
+# Compiler flags:
+#  -o $(TARGET) defines the name of the output file
+#  -g generates debugging symbols for gdb
+#  -O turns on basic optimization; -O3 turns on heavy optimization; omit for no optimization
+#  -march=rv64gc -mabi=lp64d =mcmodel=medany generates code for RV64GC with doubles and long/ptrs = 64 bits
+#  -static forces static linking (no dynamic shared libraries on bare metal)
+#  -lm links the math library if necessary (when #include math.h)
+#  -nostdlib avoids inserting standard startup files and default libraries 
+#     because we are using crt.s on bare metal
+#  -fno-tree-loop-distribute-patterns turns replacing loops with memcpy/memset in the std library 
+#  -T specifies the linker file
+#  -I specifies the include path (e.g. for util.h)
+#  The last line defines the C files to compile.  
+#    crt.S is needed as our startup file to initialize the processor
+#    syscalls.c implements printf through the HTIF for Spike
+# other flags from riscv-tests makefiles that don't seem to be important
+#	  -ffast-math -DPREALLOCATE=1 -std=gnu99  \
+#     -fno-common -fno-builtin-printf -nostartfiles -lgcc \
+
+clean:
+	rm -f $(TARGET) $(TARGET).objdump

examples/C/fir/fir.c

@@ -0,0 +1,43 @@
+// fir.c
+// David_Harris@hmc.edu 20 January 2022
+// Finite Impulse Response Filter
+
+#include <stdio.h>  // supports printf
+#include <math.h>
+#include "util.h"   // supports verify
+
+void fir(int N, int M, double X[], double c[], double Y[]) {
+  int i, n;
+  double sum; 
+
+  for (n=0; n<N; n++) {
+      sum = 0;
+      for (i=0; i<M; i++) {
+          sum += c[i]*X[n-i+(M-1)];
+      }
+      Y[n] = sum;
+  }
+}
+
+int main(void) {
+    double X[20] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20};
+    double c[5] = {0.2, 0.2, 0.2, 0.2, 0.2};
+    double Y[15];
+    double Yexpected[15] = {3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17}; 
+ 
+    setStats(1);
+    fir(15, 5, X, c, Y);
+    setStats(0);
+    for (int i=0; i<15; i++)  {
+        int tmp = Y[i];
+        printf("Y[%d] = %d\n", i, tmp);
+    }
+    // verifyDouble doesn't work exaclty because of rounding, so check for almost equal
+    for (int i=0; i<15; i++) {
+        if (fabs(Y[i] - Yexpected[i]) > 1e-10) {
+            //printf("bad case %d\n", i);
+            return 1;
+        }
+    }
+    return 0;
+}