Added unit testing

Makefile

@@ -25,3 +25,8 @@ clean:
 .SILENT: run
 run: all
 	./$(BUILD_DIR)/$(NAME)
+
+.PHONY: tests
+.SILENT: tests
+tests: all
+	make -C tests

README.md

@@ -1,5 +1,12 @@
 # vriscv - a risc-v simulator
 
+## Unit tests
+
+Unit tests can be compiled and run using :
+```
+make tests
+```
+
 ## Resources used
 
 Juraj's Blog, mostly:

tests/Makefile

@@ -0,0 +1,22 @@
+AS=riscv32-elf-as
+LD=riscv32-elf-ld
+BUILD_DIR=../build/tests/
+
+S_FILES := $(shell find ./ -name '*.s')
+NAMES = $(basename $(S_FILES))
+OBJECTS=$(patsubst %, $(BUILD_DIR)/%, $(NAMES))
+
+all: $(OBJECTS) run
+
+$(BUILD_DIR):
+	mkdir -p $(BUILD_DIR)
+
+$(BUILD_DIR)/%.o: %.s | $(BUILD_DIR)
+	$(AS) $^ -o $@
+
+$(BUILD_DIR)/%: $(BUILD_DIR)/%.o | $(BUILD_DIR)
+	$(LD) $^ -o $@ -nostdlib
+
+.SILENT: run
+run:
+	bash test.sh

tests/addi.s

@@ -0,0 +1,4 @@
+.global _start
+_start:
+    addi a0, zero, 0xBA
+    ebreak

tests/beq.s

@@ -0,0 +1,31 @@
+.global _start
+_start:
+    # Set base value of a0 to 'test failed'
+    addi a0, zero, 1
+
+    # Set A, B values of t0/t1, to test equality
+    addi t0, zero, 0xA
+    addi t1, zero, 0xB
+    beq t0, t1, eq0
+
+    # Inequality passed, now test equality
+    addi t0, zero, 0xA
+    addi t1, zero, 0xA
+    beq t0, t1, eq1
+
+    # On failure, return
+    ebreak
+
+eqNeg:
+    # All passed
+    addi a0, zero, 0
+    ebreak
+
+eq0:
+    # Inequality failed
+    ebreak
+
+eq1:
+    # Equality passed ; now try to test a negative offset case
+    beq t0, t1, eqNeg
+    ebreak

tests/jal.s

@@ -0,0 +1,21 @@
+.global _start
+_start:
+    # Set base value of a0 to 'test failed'
+    addi a0, zero, 1
+
+    # Construct value that ra should have in t0
+    auipc t0, 0
+    addi t0, t0, 12
+    # Jump and link
+    jal ra, fn0
+    ebreak
+
+fn0:
+    # Check ra value with our t0 construct
+    beq t0, ra, eq0
+    ebreak
+
+eq0:
+    # All good
+    addi a0, zero, 0
+    ebreak

tests/jalr.s

@@ -0,0 +1,46 @@
+.global _start
+_start:
+    # Set base value of a0 to 'test failed'
+    addi a0, zero, 1
+
+    # Setup a stack
+    addi sp, sp, 0x100
+
+    # Try to call a simple function
+    jal fn1
+
+    # Try to call two imbricated functions
+    jal fn0
+
+    auipc t0, 0
+    jalr ra, 12(t0)
+
+    ebreak
+
+# just_after : address is 12 bytes after auipc
+just_after:
+    addi a0, zero, 0
+    ret
+    ebreak
+
+# fn0 : function that calls fn1 and returns
+fn0:
+    # Make space on the stack
+    addi sp, sp, -4
+    # Save ra
+    sw ra, 0(sp)
+
+    # Call fn1
+    jal fn1
+
+    # Restore ra and stack
+    lw ra, 0(sp)
+    addi sp, sp, 4
+
+    ret
+    ebreak
+
+# fn1 : just return
+fn1:
+    ret
+    ebreak

tests/mv.s

@@ -0,0 +1,5 @@
+.global _start
+_start:
+    addi a1, zero, 0xBA
+    mv a0, a1
+    ebreak

tests/swlw.s

@@ -0,0 +1,21 @@
+.global _start
+_start:
+    # Set base value of a0 to 'test failed'
+    addi a0, zero, 1
+
+    # Store Word 0xBA at 0x104
+    addi t0, zero, 0x100
+    addi t1, zero, 0xBA
+    sw t1, 4(t0)
+
+    # Load Word at 0x104 in t0
+    lw t0, 4(t0)
+
+    # Compare
+    beq t0, t1, good
+
+    ebreak
+
+good:
+    addi a0, zero, 0
+    ebreak

tests/test.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+
+GREEN="\e[32m"
+RED="\e[31m"
+CEND="\e[39m"
+
+VRISCV=../build/vriscv
+
+# test executes a test
+# Arguments: test(name, executable, expected)
+test() {
+    NAME=$1
+    TEST=$2
+    RESULT=$3
+
+    echo -ne "${NAME}""\t\t\t\t\t\t"
+    $VRISCV $TEST >/dev/null 2>&1
+    if [ $? -eq $RESULT ]; then
+        echo -e $GREEN"PASSED"$CEND
+    else
+        echo -e $RED"FAILED"$CEND
+    fi
+}
+
+test "ADDI : Add Immediate          " "../build/tests/addi " 186
+test "MV   : Move registers         " "../build/tests/mv   " 186
+test "BEQ  : Branch EQual           " "../build/tests/beq  " 0
+test "JAL  : Jump And Link          " "../build/tests/jal  " 0
+test "SWLW : Store Word Load Word   " "../build/tests/swlw " 0
+test "JALR : Jump And Link Register " "../build/tests/jalr " 0