#define STACK_SIZE 512
-#ifdef __riscv64
+#if XLEN == 64
# define LREG ld
# define SREG sd
# define REGBYTES 8
j trap_entry
handle_reset:
- la t0, trap_entry
+ // If misa doesn't exist (or is following an old spec where it has a
+ // different number), skip the next block.
+ la t0, 3f
csrw mtvec, t0
csrwi mstatus, 0
+
+ // make sure these registers exist by seeing if either S or U bits
+ // are set before attempting to zero them out.
+ csrr t1, misa
+ addi t2, x0, 1
+ slli t2, t2, 20 // U_EXTENSION
+ and t2, t1, t2
+ bne x0, t2, 1f
+ addi t2, x0, 1
+ slli t2, t2, 18 // S_EXTENSION
+ and t2, t1, t2
+ bne x0, t2, 1f
+ j 2f
+1:
csrwi mideleg, 0
csrwi medeleg, 0
+2:
csrwi mie, 0
+3:
+ la t0, trap_entry
+ csrw mtvec, t0
+ csrwi mstatus, 0
# initialize global pointer
- la gp, _gp
+.option push
+.option norelax
+ la gp, __global_pointer$
+.option pop
# initialize stack pointer
la sp, stack_top
+ # Clear all hardware triggers
+ li t0, ~0
+1:
+ addi t0, t0, 1
+ csrw CSR_TSELECT, t0
+ csrw CSR_TDATA1, zero
+ csrr t1, CSR_TSELECT
+ beq t0, t1, 1b
+
# perform the rest of initialization in C
j _init