Adding odd solutions

examples/exercises/17p1/17p1.c

@@ -0,0 +1,6 @@
+#include <string.h>
+
+int main(void) {
+    char str[] = "Hello Wally!";
+    return strlen(str);
+}

examples/exercises/17p1/Makefile

@@ -0,0 +1,11 @@
+TARGET = 17p1
+
+$(TARGET).objdump: $(TARGET).elf
+	riscv64-unknown-elf-objdump -D $(TARGET).elf > $(TARGET).objdump
+    
+$(TARGET).elf: $(TARGET).c Makefile
+	riscv64-unknown-elf-gcc -g -o $(TARGET) -march=rv64gc_zbb -mabi=lp64 -mcmodel=medany \
+	    -nostartfiles -T../../link/link.ld $(TARGET).c -o $(TARGET).elf
+
+clean:
+	rm -f $(TARGET).elf $(TARGET).objdump

examples/exercises/3p1/3p1.S

@@ -0,0 +1,10 @@
+.section .text.init
+.globl rvtest_entry_point
+
+rvtest_entry_point:
+    li t0, 0x42
+    li t1, 0xED
+    add t2, t0, t1
+
+self_loop:
+    j self_loop

examples/exercises/3p1/Makefile

@@ -0,0 +1,13 @@
+TARGET = 3p1
+
+$(TARGET).objdump: $(TARGET).elf
+	riscv64-unknown-elf-objdump -D $(TARGET).elf > $(TARGET).objdump
+    
+$(TARGET).elf: $(TARGET).S Makefile
+	riscv64-unknown-elf-gcc -g -o $(TARGET) -march=rv64gc -mabi=lp64 -mcmodel=medany \
+	    -nostartfiles -T../../link/link.ld $(TARGET).S -o $(TARGET).elf
+
+clean:
+	rm -f $(TARGET).elf $(TARGET).objdump
+
+

examples/exercises/3p13/3p13.c

@@ -0,0 +1,6 @@
+#include <string.h>
+
+int main(void) {
+    char str[] = "Hello Wally!";
+    return strlen(str);
+}

examples/exercises/3p13/Makefile

@@ -0,0 +1,11 @@
+TARGET = 3p13
+
+$(TARGET).objdump: $(TARGET).elf
+	riscv64-unknown-elf-objdump -D $(TARGET).elf > $(TARGET).objdump
+    
+$(TARGET).elf: $(TARGET).c Makefile
+	riscv64-unknown-elf-gcc -g -o $(TARGET) -march=rv32gc -mabi=ilp32 -mcmodel=medany \
+	    -nostartfiles -T../../link/link.ld $(TARGET).c -o $(TARGET).elf
+
+clean:
+	rm -f $(TARGET).elf $(TARGET).objdump

examples/exercises/3p15/Makefile

@@ -0,0 +1,19 @@
+TARGET = sumtest
+
+$(TARGET).objdump: $(TARGET)
+	riscv64-unknown-elf-objdump -D $(TARGET) > $(TARGET).objdump
+    
+$(TARGET): $(TARGET).S sum.S Makefile
+	riscv64-unknown-elf-gcc -g -o $(TARGET) -march=rv64gc -mabi=lp64 -mcmodel=medany \
+	    -nostartfiles -T../../link/link.ld $(TARGET).S sum.S
+
+sim:
+	riscv_sim_RV64 -T $(TARGET).signature.output --signature-granularity 8 $(TARGET) 
+	diff --ignore-case $(TARGET).signature.output $(TARGET).reference_output || exit
+	echo "Signature matches! Success!"
+
+clean:
+	rm -f $(TARGET) $(TARGET).objdump $(TARGET).signature.output
+
+
+

examples/exercises/3p15/sum.S

@@ -0,0 +1,32 @@
+// sum.s
+// David_Harris@hmc.edu 24 December 2021
+// Add up numbers from 1 to N.
+
+// result in s0, i in s1, N in a0, return answer in a0
+//
+// long sum(long N) {
+//   long result, i;
+//   result = 0;
+//   for (i=1; i<=N; i++) result = result + i;
+//   return result;
+// }
+
+.global sum
+sum:
+    addi sp, sp, -16    # make room to save s0 and s1 on the stack
+    sd s0, 0(sp)
+    sd s1, 8(sp)
+
+    li s0, 0            # result = 0
+    li s1, 1            # i = 1
+for: bgt s1, a0, done   # exit loop if i > n
+    add s0, s0, s1      # result = result + i
+    addi s1, s1, 1      # i++
+    j for               # repeat
+
+done:
+    mv a0, s0           # put result in a0 to return
+    ld s0, 0(sp)        # restore s0 and s1 from stack
+    ld s1, 8(sp)
+    addi sp, sp, 16  
+    ret                 # return from function

examples/exercises/3p15/sumtest.S

@@ -0,0 +1,43 @@
+// sumtest.S
+// David_Harris@hmc.edu 24 December 2021
+
+.global rvtest_entry_point
+rvtest_entry_point:
+    la sp, topofstack   # Initialize stack pointer
+    la t0, N            # get address of N in data
+    ld a0, 0(t0)        # load N
+    csrr s8, instret    # count instructions before call
+    jal sum             # call sum(N)
+    csrr s9, instret    # count instructions after call
+    sub s9, s9, s8      # length of call
+    la t0, begin_signature  # address of signature
+    sd a0, 0(t0)        # store sum(N) in signature
+    sd s9, 8(t0)        # record performance
+
+write_tohost:
+    la t1, tohost
+    li t0, 1            # 1 for success, 3 for failure
+    sd t0, 0(t1)        # send success code
+
+self_loop:
+    j self_loop         # wait
+    
+.section .tohost 
+tohost:                 # write to HTIF
+    .dword 0
+fromhost:
+    .dword 0
+
+.data
+N:
+    .dword 6
+
+.EQU XLEN,64
+begin_signature:
+    .fill 2*(XLEN/32),4,0xdeadbeef    # 
+end_signature:
+
+# Initialize stack with room for 512 bytes
+.bss
+    .space 512
+topofstack:

examples/exercises/3p15/sumtest.reference_output

@@ -0,0 +1,2 @@
+0000000000000015
+0000000000000025

examples/exercises/3p3/Makefile

@@ -0,0 +1,19 @@
+TARGET = sumtest
+
+$(TARGET).objdump: $(TARGET)
+	riscv64-unknown-elf-objdump -D $(TARGET) > $(TARGET).objdump
+    
+$(TARGET): $(TARGET).S sum.S Makefile
+	riscv64-unknown-elf-gcc -g -o $(TARGET) -march=rv64gc -mabi=lp64 -mcmodel=medany \
+	    -nostartfiles -T../../link/link.ld $(TARGET).S sum.S
+
+sim:
+	spike +signature=$(TARGET).signature.output +signature-granularity=8 $(TARGET)
+	diff --ignore-case $(TARGET).signature.output $(TARGET).reference_output || exit
+	echo "Signature matches! Success!"
+
+clean:
+	rm -f $(TARGET) $(TARGET).objdump $(TARGET).signature.output
+
+
+

examples/exercises/3p3/sum.S

@@ -0,0 +1,32 @@
+// sum.s
+// David_Harris@hmc.edu 24 December 2021
+// Add up numbers from 1 to N.
+
+// result in s0, i in s1, N in a0, return answer in a0
+//
+// long sum(long N) {
+//   long result, i;
+//   result = 0;
+//   for (i=1; i<=N; i++) result = result + i;
+//   return result;
+// }
+
+.global sum
+sum:
+    addi sp, sp, -16    # make room to save s0 and s1 on the stack
+    sd s0, 0(sp)
+    sd s1, 8(sp)
+
+    li s0, 0            # result = 0
+    li s1, 1            # i = 1
+for: bgt s1, a0, done   # exit loop if i > n
+    add s0, s0, s1      # result = result + i
+    addi s1, s1, 1      # i++
+    j for               # repeat
+
+done:
+    mv a0, s0           # put result in a0 to return
+    ld s0, 0(sp)        # restore s0 and s1 from stack
+    ld s1, 8(sp)
+    addi sp, sp, 16  
+    ret                 # return from function

examples/exercises/3p3/sumtest.S

@@ -0,0 +1,43 @@
+// sumtest.S
+// David_Harris@hmc.edu 24 December 2021
+
+.global rvtest_entry_point
+rvtest_entry_point:
+    la sp, topofstack   # Initialize stack pointer
+    la t0, N            # get address of N in data
+    ld a0, 0(t0)        # load N
+    csrr s8, instret    # count instructions before call
+    jal sum             # call sum(N)
+    csrr s9, instret    # count instructions after call
+    sub s9, s9, s8      # length of call
+    la t0, begin_signature  # address of signature
+    sd a0, 0(t0)        # store sum(N) in signature
+    sd s9, 8(t0)        # record performance
+
+write_tohost:
+    la t1, tohost
+    li t0, 1            # 1 for success, 3 for failure
+    sd t0, 0(t1)        # send success code
+
+self_loop:
+    j self_loop         # wait
+    
+.section .tohost 
+tohost:                 # write to HTIF
+    .dword 0
+fromhost:
+    .dword 0
+
+.data
+N:
+    .dword 6
+
+.EQU XLEN,64
+begin_signature:
+    .fill 2*(XLEN/32),4,0xdeadbeef    # 
+end_signature:
+
+# Initialize stack with room for 512 bytes
+.bss
+    .space 512
+topofstack:

examples/exercises/3p3/sumtest.reference_output

@@ -0,0 +1,2 @@
+0000000000000015
+0000000000000025

examples/exercises/3p5/Makefile

@@ -0,0 +1,32 @@
+TARGET = matvecmul
+
+$(TARGET).objdump: $(TARGET)
+	riscv64-unknown-elf-objdump -S -D $(TARGET) > $(TARGET).objdump
+    
+$(TARGET): $(TARGET).c Makefile
+	riscv64-unknown-elf-gcc -o $(TARGET) -gdwarf-2 -O\
+	  -march=rv64gc -mabi=lp64d -mcmodel=medany \
+	  -nostdlib -static -lm -fno-tree-loop-distribute-patterns \
+	  -T../../C/common/test.ld -I../../C/common \
+	  $(TARGET).c ../../C/common/crt.S ../../C/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/exercises/3p5/matvecmul.c

@@ -0,0 +1,22 @@
+#include <stdio.h>  // supports printf
+#include "util.h"   // supports verify
+
+// Matrix-vector multiplication y = Ax.  
+// A is an m rows x n columns matrix.
+void matvecmul(int A[], int x[], int y[], int m, int n) {
+ 	int i, j, sum;
+	for (i=0; i<m; i = i + 1) {
+		sum = 0;
+		for (j=0; j<n; j = j + 1) 
+			sum = sum + A[i*n+j] * x[j];
+		y[i] = sum;
+	}
+}
+
+void main(void) {
+  int A[6] = {1, 2, 3, 4, 5, 6};
+  int x[3] = {7, 8, 9};
+  int y[2];
+  
+  matvecmul(A, x, y, 2, 3);
+}

examples/exercises/3p7/Makefile

@@ -0,0 +1,32 @@
+TARGET = fir
+
+$(TARGET).objdump: $(TARGET)
+	riscv64-unknown-elf-objdump -S -D $(TARGET) > $(TARGET).objdump
+    
+$(TARGET): $(TARGET).c Makefile
+	riscv64-unknown-elf-gcc -o $(TARGET) -gdwarf-2 -O2\
+	  -march=rv64gc -mabi=lp64d -mcmodel=medany \
+	  -nostdlib -static -lm -fno-tree-loop-distribute-patterns \
+	  -T../../C/common/test.ld -I../../C/common \
+	  $(TARGET).c ../../C/common/crt.S ../../C/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/exercises/3p7/fir.c

@@ -0,0 +1,83 @@
+#include <stdio.h>  // supports printf
+#include "util.h"   // supports verify
+
+// Add two Q1.31 fixed point numbers
+int add_q31(int a, int b) {
+	return a + b;
+}
+
+// Multiplly two Q1.31 fixed point numbers
+int mul_q31(int a, int b) {
+	long res = (long)a * (long)b;
+	int result = res >> 31; // shift right to get the 32-bit result; this is equivalent to shifting left by 1 and discarding the bottom 32 bits
+	//printf("mul_q31: a = %x, b = %x, res = %lx, result = %x\n", a, b, res, result);
+	return result; 
+}
+
+
+// low pass filter x with coefficients c, result in y
+// n is the length of x, m is the length of c
+// y[i] = c[0]*x[i] + c[1]*x[i+1] + ... + c[m-1]*x[i+m-1]
+// inputs in Q1.31 format
+void fir(int x[], int c[], int y[], int n, int m) {
+	int i, j;
+	for (j=0; j<n-m+1; j++) {
+		y[j] = 0;
+		for (i=0; i<m; i++) 
+			y[j] = add_q31(y[j], mul_q31(c[i], x[j-i+(m-1)]));
+	}
+}
+
+int main(void) {
+	int32_t sin_table[20] = { // in Q1.31 format
+		0x00000000, // sin(0*2pi/10)
+		0x4B3C8C12, // sin(1*2pi/10)
+		0x79BC384D, // sin(2*2pi/10)
+		0x79BC384D, // sin(3*2pi/10)
+		0x4B3C8C12, // sin(4*2pi/10)
+		0x00000000, // sin(5*2pi/10)
+		0xB4C373EE, // sin(6*2pi/10)
+		0x8643C7B3, // sin(7*2pi/10)
+		0x8643C7B3, // sin(8*2pi/10)
+		0xB4C373EE, // sin(9*2pi/10)
+		0x00000000, // sin(10*2pi/10)
+		0x4B3C8C12, // sin(11*2pi/10)
+		0x79BC384D, // sin(12*2pi/10)
+		0x79BC384D, // sin(13*2pi/10)
+		0x4B3C8C12, // sin(14*2pi/10)
+		0x00000000, // sin(15*2pi/10)
+		0xB4C373EE, // sin(16*2pi/10)
+		0x8643C7B3, // sin(17*2pi/10)
+		0x8643C7B3, // sin(18*2pi/10)
+		0xB4C373EE  // sin(19*2pi/10)
+	};  
+	int lowpass[4] = {0x20000001, 0x20000002, 0x20000003, 0x20000004}; // 1/4 in Q1.31 format
+	int y[17];
+  	int expected[17] = { // in Q1.31 format
+		0x4fad3f2f,
+		0x627c6236,
+		0x4fad3f32,
+		0x1e6f0e17,
+		0xe190f1eb,
+		0xb052c0ce,
+		0x9d839dc6,
+		0xb052c0cb,
+		0xe190f1e6,
+		0x1e6f0e12,
+		0x4fad3f2f,
+		0x627c6236,
+		0x4fad3f32,
+		0x1e6f0e17,
+		0xe190f1eb,
+		0xb052c0ce,
+		0x9d839dc6
+	};
+
+  	setStats(1);		// record initial mcycle and minstret
+	fir(sin_table, lowpass, y, 20, 4);
+	setStats(0);		// record elapsed mcycle and minstret
+	for (int i=0; i<17; i++) {
+		printf("y[%d] = %x\n", i, y[i]);
+	}
+  	return verify(16, y, expected); // check the 1 element of s matches expected. 0 means success
+}

examples/exercises/3p9/Makefile

@@ -0,0 +1,32 @@
+TARGET = inline
+
+$(TARGET).objdump: $(TARGET)
+	riscv64-unknown-elf-objdump -S -D $(TARGET) > $(TARGET).objdump
+    
+$(TARGET): $(TARGET).c Makefile
+	riscv64-unknown-elf-gcc -o $(TARGET) -gdwarf-2 -O\
+	  -march=rv64gc -mabi=lp64d -mcmodel=medany \
+	  -nostdlib -static -lm -fno-tree-loop-distribute-patterns \
+	  -T../../C/common/test.ld -I../../C/common \
+	  $(TARGET).c ../../C/common/crt.S ../../C/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/exercises/3p9/inline.c

@@ -0,0 +1,11 @@
+#include <stdio.h>  // supports printf
+int main(void) {
+	int a = 3;
+	int b = 4;
+	int c;
+	// compute c = a + 2*b using inline assembly
+	asm volatile("slli %0, %1, 1" : "=r" (c) : "r" (b));	      // c = b << 1
+	asm volatile("add %0, %1, %2" : "=r" (c) : "r" (a), "r" (c)); // c = a + c
+
+	printf("c = %d\n", c);
+}