Remove old test code

There is some code that I had there after messing with some of the
topics on Uros' blog (https://popovicu.com/), but that became irrelevant
after working on some other projects (e.g. fbos) or on other examples.

This commit also brings about a major overhaul on the structure of the
project. Hopefully it's now at a more ready state.

Signed-off-by: Miquel Sabaté Solà <mikisabate@gmail.com>

5 files changed, 0 insertions, 360 deletions

diff --git a/arch/riscv/usr/Makefile b/arch/riscv/usr/Makefile
deleted file mode 100644
index b4752a3..0000000
--- a/arch/riscv/usr/Makefile
+++ /dev/null
@@ -1,19 +0,0 @@
-CC      = $(CROSS_COMPILE)gcc
-CCFLAGS =
-EXE     = basics
-
-DEBUG =
-ifneq ($(strip $(DEBUG)),)
-	CCFLAGS += -g
-endif
-
-.PHONY: all
-all: clean $(EXE)
-
-.PHONY: $(EXE)
-$(EXE):
-	$(CC) $(CCFLAGS) -o $(EXE) basics.c factorial.S string.S float.S
-
-.PHONY: clean
-clean:
-	@rm -f $(EXE)
diff --git a/arch/riscv/usr/basics.c b/arch/riscv/usr/basics.c
deleted file mode 100644
index 1d822c3..0000000
--- a/arch/riscv/usr/basics.c
+++ /dev/null
@@ -1,162 +0,0 @@
-#include <assert.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdint.h>
-#include <string.h>
-
-/*
- * Returns the factorial for the given unsigned 64-bit integer.
- *
- * Implemented in factorial.S
- */
-int factorial(uint64_t n);
-
-void test_factorial(void)
-{
-	assert(factorial(0) == 0);
-	assert(factorial(1) == 1);
-	assert(factorial(2) == 2);
-	assert(factorial(3) == 6);
-	assert(factorial(4) == 24);
-
-	printf("factorial:\t\tOK\n");
-}
-
-/*
- * Returns a pointer with the same given string but reversed. Note that the
- * string cannot be in read-only space since the reversal is done in-place.
- *
- * Implemented in string.S
- */
-char *reverse_string(char *str);
-
-void test_reverse_string(void)
-{
-	assert(reverse_string(NULL) == NULL);
-	assert(strlen(reverse_string("")) == 0);
-
-	char s1[] = "This is a string.";
-	assert(strcmp(reverse_string(s1), ".gnirts a si sihT") == 0);
-
-	char s2[] = ".";
-	assert(strcmp(reverse_string(s2), ".") == 0);
-
-	printf("reverse_string:\t\tOK\n");
-}
-
-/*
- * Returns true if the given string is a palindrome, false otherwise.
- *
- * Implemented in string.S
- */
-bool is_palindrome(char *str);
-
-void test_is_palindrome(void)
-{
-	assert(is_palindrome(NULL) == 0);
-	assert(is_palindrome("") == 0);
-	assert(is_palindrome("aba") == 1);
-	assert(is_palindrome("aaa") == 1);
-	assert(is_palindrome("This is a a si sihT") == 1);
-
-	printf("is_palindrome:\t\tOK\n");
-}
-
-/*
- * This function computes the following: ((a + b) * b) + b. Don't try to make
- * sense of it, that's the computation I ended up while messing with RISC-V
- * floating point instructions. Anyways, with this in mind, it will return if
- * the computed value is greater than 10.
- *
- * Implemented in float.S
- */
-bool greater_than_ten(double a, uint64_t b);
-
-void test_greater_than_ten(void)
-{
-	assert(!greater_than_ten(2.3, 1)); // 4.3
-	assert(greater_than_ten(2.3, 2)); // 10.6
-
-	printf("greater_than_ten:\tOK\n");
-}
-
-/*
- * Atomically add the integer pointed by `a` with the given `value`.
- * this is a function, I've checked that the assembly produced by GCC on a
- * decent optimization level actually inlines this.
- */
-static inline void atomic_add(uint64_t *a, uint64_t value)
-{
-	/*
-	 * The execution is a mere `amoadd` instruction, but it will set on `t0` the
-	 * result. If it fails (e.g. the address was already being used), then `t0 =
-	 * 0` and `beqz` will instruct it to try again.
-	 *
-	 * Note that on the board I'm using the 'Zawrs' extension is not available.
-	 * Otherwise I could have re-arranged to code to something like this:
-	 *
-	 *     amoadd.d t0, %1, %0
-	 *     bnez t0, .Latomic_add_done
-	 *     wrs.nto
-	 *  .Latomic_add_done:
-	 *
-	 * This is an extra instruction but it saves on power if the memory address
-	 * happens to be used at access time.
-	 *
-	 * As for the 'A' RISC-V specific constraint, it means "An address that is
-	 * held in a general-purpose register". GCC will then do the magic and
-	 * convert it to `amoadd.d t0, a1, (a0)` or something like that. Note that
-	 * we have to pass the '+' constraint modifier because the address will be
-	 * both read and written atomically.
-	 *
-	 * See: https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html.
-	 */
-	asm volatile(".Latomic_add_retry:\n\t"
-				 "amoadd.d t0, %1, %0\n\t"
-				 "beqz t0, .Latomic_add_retry"
-				 : "+A"(*a)
-				 : "r"(value)
-				 : "t0", "memory");
-}
-
-void test_atomic_add(void)
-{
-	uint64_t i = 4;
-
-	atomic_add(&i, 0);
-	assert(i == 4);
-
-	atomic_add(&i, 2);
-	assert(i == 6);
-
-	printf("atomic_add:\t\tOK\n");
-}
-
-extern int mstrcmp(const char *s1, const char *s2);
-
-void test_mstrcmp(void)
-{
-	char *strings[] = {
-		"hello", "", "iello", "helloa", "contammusaaquellhomedegranarditquetantissimerra",
-	};
-
-	for (uint64_t i = 0; i < 1000000000; i++) {
-		assert(mstrcmp(strings[0], strings[0]) == 0);
-		assert(mstrcmp(strings[0], strings[1]) > 0);
-		assert(mstrcmp(strings[0], strings[2]) < 0);
-		assert(mstrcmp(strings[0], strings[3]) < 0);
-		assert(mstrcmp(strings[0], strings[4]) > 0);
-	}
-
-	printf("mstrcmp:\t\tOK\n");
-}
-
-int main()
-{
-	test_factorial();
-	test_reverse_string();
-	test_is_palindrome();
-	test_greater_than_ten();
-	test_atomic_add();
-	test_mstrcmp();
-}
diff --git a/arch/riscv/usr/factorial.S b/arch/riscv/usr/factorial.S
deleted file mode 100644
index 7e3df12..0000000
--- a/arch/riscv/usr/factorial.S
+++ /dev/null
@@ -1,28 +0,0 @@
-.text
-.globl factorial
-.type factorial, @function
-
-factorial:
-	// If input <= 1, just return the given thing.
-	addi t0, zero, 1
-	bgt a0, t0, else
-	jr ra
-else:
-	// Preserve the argument and the return address before the call.
-	addi sp, sp, -16
-	sd a0, 0(sp)
-	sd ra, 8(sp)
-
-	// Call the same function but with a value of argument-1.
-	addi a0, a0, -1
-	call factorial
-
-	// Restore back the original argument and the return address. Then multiply
-	// the original argument with the returned one from the previous call.
-	ld t1, 0(sp)
-	ld ra, 8(sp)
-	addi sp, sp, 16
-	mul a0, t1, a0
-
-	// And return to the caller.
-	jr ra
diff --git a/arch/riscv/usr/float.S b/arch/riscv/usr/float.S
deleted file mode 100644
index f481f3e..0000000
--- a/arch/riscv/usr/float.S
+++ /dev/null
@@ -1,40 +0,0 @@
-.text
-.globl greater_than_ten
-.type greater_than_ten, @function
-
-// bool greater_than_ten(double a, uint64_t b);
-greater_than_ten:
-    // Upon entry a -> fa0; and b -> a0. That is, the ABI increments the
-    //(f)a<n> register per argument type.
-
-    // Change the rounding to "Rounds Towards Zero" (bits: 0b001).
-    li t0, 0b001
-    fsrm t0
-
-    // Convert the second parameter to double.
-    fcvt.d.lu ft0, a0
-
-    // ret = a + b
-    fadd.d fa0, fa0, ft0
-
-    // ret = (ret * b) + b
-    fmv.d ft1, ft0
-    fmadd.d fa0, fa0, ft0, ft1
-
-    // Now we need to compare the number with 10.0. There are multiple ways to
-    // load a floating point immediate:
-    //   1. Loading an integer immediate and then convert it into a double. This
-    //      is discouraged on the RISC-V assembly manual.
-    //   2. Load a double with `fld` from a memory location on the data section.
-    //   3. Load a floating point immediate with `fli` (requires the `Zfa`
-    //      extension).
-    // I don't have the `Zfa` extension on my board, so I'm opting for the
-    // second way.
-    fld ft1, .TEN, t0
-    fle.d a0, ft1, fa0
-
-    ret
-
-.data
-.TEN:
-    .double 10.0
diff --git a/arch/riscv/usr/string.S b/arch/riscv/usr/string.S
deleted file mode 100644
index 3878074..0000000
--- a/arch/riscv/usr/string.S
+++ /dev/null
@@ -1,111 +0,0 @@
-.text
-
-.globl reverse_string
-.type reverse_string, @function
-
-// char * reverse_string(char *str);
-reverse_string:
-    // Return early on null pointer.
-    beq a0, zero, end
-
-    // Preserve the original pointer.
-    addi sp, sp, -8
-    sd a0, 0(sp)
-
-    // Set `t0` to point to the end of the string.
-    add t0, a0, zero
-set_end_ptr:
-    lbu t2, 0(t0)
-    beq t2, zero, end_ptr_done
-    addi t0, t0, 1
-    j set_end_ptr
-
-    // We are done iterating, if `a0` and `t0` are equal, then there's nothing
-    // to be done and we can return early. Otherwise decrement `t0` so it points
-    // to the byte right before the null termination.
-end_ptr_done:
-    beq a0, t0, reverse_done
-    addi t0, t0, -1
-
-reverse_loop:
-    // Swap values between the two pointers.
-    lb t1, 0(a0)
-    lb t2, 0(t0)
-    sb t1, 0(t0)
-    sb t2, 0(a0)
-
-    // Move pointers and check whether the pointers have already crossed. If
-    // they have not crossed yet there is still looping to be done. Otherwise
-    // we are done.
-    addi a0, a0, 1
-    addi t0, t0, -1
-    bltu a0, t0, reverse_loop
-
-reverse_done:
-    // Restore things back and return to the caller.
-    ld a0, 0(sp)
-    addi sp, sp, 8
-end:
-    jr ra
-
-.globl is_palindrome
-.type is_palindrome, @function
-
-// bool is_palindrome(char *str);
-is_palindrome:
-    // Return early on null pointer.
-    beq a0, zero, palindrome_no
-
-    // Set `t0` to point to the end of the string.
-    add t0, a0, zero
-pal_set_end_ptr:
-    lbu t2, 0(t0)
-    beq t2, zero, pal_end_ptr_done
-    addi t0, t0, 1
-    j pal_set_end_ptr
-
-    // We are done iterating, if `a0` and `t0` are equal, then there's nothing
-    // to be done and we can return early. Otherwise decrement `t0` so it points
-    // to the byte right before the null termination.
-pal_end_ptr_done:
-    beq a0, t0, palindrome_no
-    addi t0, t0, -1
-
-pal_loop:
-    // Swap values between the two pointers.
-    lb t1, 0(a0)
-    lb t2, 0(t0)
-    bne t1, t2, palindrome_no
-
-    // Move pointers and check whether the pointers have already crossed. If
-    // they have not crossed yet there is still looping to be done. Otherwise
-    // we are done.
-    addi a0, a0, 1
-    addi t0, t0, -1
-    bleu a0, t0, pal_loop
-
-palindrome_yes:
-    li a0, 1
-    jr ra
-
-palindrome_no:
-    li a0, 0
-    jr ra
-
-.globl mstrcmp
-.type mstrcmp, @function
-
-// int mstrcmp(const char *, const char *);
-mstrcmp:
-1:
-	lbu t0, 0(a0)
-	lbu t1, 0(a1)
-	bne t0, t1, 2f
-	addi a0, a0, 1
-	addi a1, a1, 1
-	bnez t0, 1b
-	li a0, 0
-	ret
-2:
-	sub a0, t0, t1
-	ret