updated before 3rd class

code/asm/asm2c/test.c

@@ -1,5 +1,10 @@
+/*
+ * a0 --> a
+ * a1 --> b
+ * c  <-- a0
+ */
 int foo(int a, int b)
 {
-	int sum = a + b;
-	return sum;
+	int c = a + b;
+	return c;
 }

code/asm/asm2c/test.s

@@ -1,23 +1,28 @@
-# ASM call C
-
-	.text			# Define beginning of text section
-	.global	_start		# Define entry _start
-	.global	foo		# foo is a C function defined in test.c
-
-_start:
-	la sp, stack_end	# prepare stack for calling functions
-
-	li a0, 1
-	li a1, 2
-	call foo 
-
-stop:
-	j stop			# Infinite loop to stop execution
-
-stack_start:
-	.rept 10
-	.word 0
-	.endr
-stack_end:
-
-	.end			# End of file
+# ASM call C
+
+	.text			# Define beginning of text section
+	.global	_start		# Define entry _start
+	.global	foo		# foo is a C function defined in test.c
+
+_start:
+	la sp, stack_end	# prepare stack for calling functions
+
+	# RISC-V uses a0 ~ a7 to transfer parameters
+	li a0, 1
+	li a1, 2
+	call foo
+	# RISC-V uses a0 & a1 to transfer return value
+	# check value of a0
+
+stop:
+	j stop			# Infinite loop to stop execution
+
+	nop			# just for demo effect
+
+stack_start:
+	.rept 10
+	.word 0
+	.endr
+stack_end:
+
+	.end			# End of file

code/asm/c2asm/test.c

@@ -1,11 +1,19 @@
 int foo(int a, int b)
 {
-	int sum;
-	asm volatile(
-		"nop\n"
+	int c;
+
+	asm volatile (
+		"add %[sum], %[add1], %[add2]" 
+		:[sum]"=r"(c)
+		:[add1]"r"(a), [add2]"r"(b)
+	);
+
+/*
+	asm volatile (
 		"add %0, %1, %2" 
-		:"=r"(sum)
+		:"=r"(c)
 		:"r"(a), "r"(b)
 	);
-	return sum;
+*/
+	return c;
 }

code/asm/c2asm/test.s

@@ -14,6 +14,8 @@ _start:
 stop:
 	j stop			# Infinite loop to stop execution
 
+	nop			# just for demo effect
+
 stack_start:
 	.rept 10
 	.word 0

code/asm/rule.mk

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/00-bootstrap/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/01-helloRVOS/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/02-memanagement/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/03-contextswitch/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/04-multitask/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/05-traps/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/06-interrupts/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/07-hwtimer/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/08-preemptive/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/09-lock/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/10-swtimer/Makefile

@@ -1,5 +1,5 @@
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 QEMU = qemu-system-riscv32
 QFLAGS = -nographic -smp 1 -machine virt -bios none

code/os/11-syscall/Makefile

@@ -1,7 +1,7 @@
 SYSCALL = y
 
 CROSS_COMPILE = riscv64-unknown-elf-
-CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -g -Wall
+CFLAGS = -nostdlib -fno-builtin -march=rv32ima -mabi=ilp32 -g -Wall
 
 ifeq ($(SYSCALL), y)
 CFLAGS += -D CONFIG_SYSCALL