fix rtl gpr zero

runtime/newlib/newlib.c

@@ -274,14 +274,6 @@ void * _sbrk (int nbytes)
  //    }
 }       /* _sbrk () */
 
-
-void _exit(int val)
-{
-	// vx_print_str("Hello from exit\n");
-	vx_tmc(0);
-}
-
-
 int _open(const char *name, int flags, int mode)
 {
 	// char * write_buffer = (char *) FILE_IO_WRITE;

runtime/startup/vx_start.S

@@ -4,27 +4,35 @@
 .global _start
 .type   _start, @function
 _start:
-    la a1, vx_set_sp
-    li a0, NUM_WARPS    # activate all warps
-    .word 0x00b5106b # wspawn a0(numWarps), a1(PC SPAWN)
-    jal vx_set_sp
-    li a0, 1
-    .word 0x0005006b    # back to single thread
-    # Initialize global pointerp
-    # call __cxx_global_var_init
-    # Clear the bss segment
-    la      a0, _edata
-    la      a2, _end
-    sub     a2, a2, a0
-    li      a1, 0
-    call    memset
-    la      a0, __libc_fini_array   # Register global termination functions
-    call    atexit                  # to be called upon exit
-    call    __libc_init_array       # Run global initialization functions
-    call    main
-    tail    exit
+  la a1, vx_set_sp
+  li a0, NUM_WARPS    # activate all warps
+  .word 0x00b5106b # wspawn a0(numWarps), a1(PC SPAWN)
+  jal vx_set_sp
+  li a0, 1
+  .word 0x0005006b    # back to single thread
+  # Initialize global pointerp
+  # call __cxx_global_var_init
+  # Clear the bss segment
+  la      a0, _edata
+  la      a2, _end
+  sub     a2, a2, a0
+  li      a1, 0
+  call    memset
+  la      a0, __libc_fini_array   # Register global termination functions
+  call    atexit                  # to be called upon exit
+  call    __libc_init_array       # Run global initialization functions
+  call    main
+  tail    exit
 .size  _start, .-_start
 
+.section .text
+.type _exit, @function
+.global _exit
+_exit:
+  li a0, 0
+  .word 0x0005006b    # disable all threads
+
+
 .section .text
 .type vx_set_sp, @function
 .global vx_set_sp

runtime/tests/simple/Makefile

@@ -1,8 +1,8 @@
 
 COMP     = ~/dev/riscv-gnu-toolchain/drops/bin/riscv32-unknown-elf-g++
-#COMP     = /opt/riscv-new/drops/bin/riscv32-unknown-elf-g++
 
-CC_FLAGS = -march=rv32im -mabi=ilp32 -O3 -Wl,-Bstatic,-T,../../startup/vx_link.ld -ffreestanding -nostdlib
+CC_FLAGS = -march=rv32im -mabi=ilp32 -O3 -Wl,-Bstatic,-T,../../startup/vx_link.ld 
+CC_FLAGS += -nostartfiles -ffreestanding -fno-rtti -fno-exceptions -Wl,--gc-sections 
 
 DMP  = ~/dev/riscv-gnu-toolchain/drops/bin/riscv32-unknown-elf-objdump
 CPY  = ~/dev/riscv-gnu-toolchain/drops/bin/riscv32-unknown-elf-objcopy
@@ -17,8 +17,9 @@ VX_FIO  = ../../fileio/fileio.S
 
 VX_MAIN = vx_simple_main
 
-LIBS    = ~/dev/riscv-gnu-toolchain/drops/riscv32-unknown-elf/lib/libc.a ~/dev/riscv-gnu-toolchain/drops/riscv32-unknown-elf/lib/libstdc++.a -static-libgcc -lgcc
-#LIBS    = /opt/riscv-new/drops/riscv32-unknown-elf/lib/libc.a /opt/riscv-new/drops/riscv32-unknown-elf/lib/libstdc++.a -static-libgcc -lgcc
+#LIBS  += ~/dev/riscv-gnu-toolchain/drops/riscv32-unknown-elf/lib/libc.a 
+#LIBS  += ~/dev/riscv-gnu-toolchain/drops/riscv32-unknown-elf/lib/libstdc++.a 
+#LIBS  += -static-libgcc -lgcc
 
 VX_SRCS = vx_simple_main.c tests.c