-#include "pcr.h"
+# See LICENSE for license details.
- .data
- .globl _heapend
- .globl environ
-_heapend:
- .word 0
-environ:
- .word 0
+#include "encoding.h"
- .text
- .globl _start
+#if __riscv_xlen == 64
+# define LREG ld
+# define SREG sd
+# define REGBYTES 8
+#else
+# define LREG lw
+# define SREG sw
+# define REGBYTES 4
+#endif
+ .section ".text.init"
+ .globl _start
_start:
li x1, 0
li x2, 0
li x30,0
li x31,0
-#ifdef __riscv64
- setpcr status, SR_S64
- setpcr status, SR_U64
-#endif
-
- # enable fp
- setpcr status, SR_EF
+ # enable FPU and accelerator if present
+ li t0, MSTATUS_FS | MSTATUS_XS
+ csrs mstatus, t0
- # enable vec
- setpcr t0, status, SR_EV
+ # make sure XLEN agrees with compilation choice
+ li t0, 1
+ slli t0, t0, 31
+#if __riscv_xlen == 64
+ bgez t0, 1f
+#else
+ bltz t0, 1f
+#endif
+2:
+ li a0, 1
+ sw a0, tohost, t0
+ j 2b
+1:
- ## if that didn't stick, we don't have an FPU, so don't initialize it
- and t0, t0, SR_EF
- beqz t0, 1f
+#ifdef __riscv_flen
+ # initialize FPU if we have one
+ la t0, 1f
+ csrw mtvec, t0
fssr x0
fmv.s.x f0, x0
fmv.s.x f30,x0
fmv.s.x f31,x0
1:
+#endif
+
+ # initialize trap vector
+ la t0, trap_entry
+ csrw mtvec, t0
+
+ # initialize global pointer
+ la gp, __global_pointer$
+
+ la tp, _end + 63
+ and tp, tp, -64
+
+ # get core id
+ csrr a0, mhartid
+ # for now, assume only 1 core
+ li a1, 1
+1:bgeu a0, a1, 1b
+
+ # give each core 128KB of stack + TLS
+#define STKSHIFT 17
+ sll a2, a0, STKSHIFT
+ add tp, tp, a2
+ add sp, a0, 1
+ sll sp, sp, STKSHIFT
+ add sp, sp, tp
+
+ j _init
+
+ .align 2
+trap_entry:
+ addi sp, sp, -272
+
+ SREG x1, 1*REGBYTES(sp)
+ SREG x2, 2*REGBYTES(sp)
+ SREG x3, 3*REGBYTES(sp)
+ SREG x4, 4*REGBYTES(sp)
+ SREG x5, 5*REGBYTES(sp)
+ SREG x6, 6*REGBYTES(sp)
+ SREG x7, 7*REGBYTES(sp)
+ SREG x8, 8*REGBYTES(sp)
+ SREG x9, 9*REGBYTES(sp)
+ SREG x10, 10*REGBYTES(sp)
+ SREG x11, 11*REGBYTES(sp)
+ SREG x12, 12*REGBYTES(sp)
+ SREG x13, 13*REGBYTES(sp)
+ SREG x14, 14*REGBYTES(sp)
+ SREG x15, 15*REGBYTES(sp)
+ SREG x16, 16*REGBYTES(sp)
+ SREG x17, 17*REGBYTES(sp)
+ SREG x18, 18*REGBYTES(sp)
+ SREG x19, 19*REGBYTES(sp)
+ SREG x20, 20*REGBYTES(sp)
+ SREG x21, 21*REGBYTES(sp)
+ SREG x22, 22*REGBYTES(sp)
+ SREG x23, 23*REGBYTES(sp)
+ SREG x24, 24*REGBYTES(sp)
+ SREG x25, 25*REGBYTES(sp)
+ SREG x26, 26*REGBYTES(sp)
+ SREG x27, 27*REGBYTES(sp)
+ SREG x28, 28*REGBYTES(sp)
+ SREG x29, 29*REGBYTES(sp)
+ SREG x30, 30*REGBYTES(sp)
+ SREG x31, 31*REGBYTES(sp)
+
+ csrr a0, mcause
+ csrr a1, mepc
+ mv a2, sp
+ jal handle_trap
+ csrw mepc, a0
+
+ # Remain in M-mode after eret
+ li t0, MSTATUS_MPP
+ csrs mstatus, t0
+
+ LREG x1, 1*REGBYTES(sp)
+ LREG x2, 2*REGBYTES(sp)
+ LREG x3, 3*REGBYTES(sp)
+ LREG x4, 4*REGBYTES(sp)
+ LREG x5, 5*REGBYTES(sp)
+ LREG x6, 6*REGBYTES(sp)
+ LREG x7, 7*REGBYTES(sp)
+ LREG x8, 8*REGBYTES(sp)
+ LREG x9, 9*REGBYTES(sp)
+ LREG x10, 10*REGBYTES(sp)
+ LREG x11, 11*REGBYTES(sp)
+ LREG x12, 12*REGBYTES(sp)
+ LREG x13, 13*REGBYTES(sp)
+ LREG x14, 14*REGBYTES(sp)
+ LREG x15, 15*REGBYTES(sp)
+ LREG x16, 16*REGBYTES(sp)
+ LREG x17, 17*REGBYTES(sp)
+ LREG x18, 18*REGBYTES(sp)
+ LREG x19, 19*REGBYTES(sp)
+ LREG x20, 20*REGBYTES(sp)
+ LREG x21, 21*REGBYTES(sp)
+ LREG x22, 22*REGBYTES(sp)
+ LREG x23, 23*REGBYTES(sp)
+ LREG x24, 24*REGBYTES(sp)
+ LREG x25, 25*REGBYTES(sp)
+ LREG x26, 26*REGBYTES(sp)
+ LREG x27, 27*REGBYTES(sp)
+ LREG x28, 28*REGBYTES(sp)
+ LREG x29, 29*REGBYTES(sp)
+ LREG x30, 30*REGBYTES(sp)
+ LREG x31, 31*REGBYTES(sp)
+
+ addi sp, sp, 272
+ mret
+
+.section ".tdata.begin"
+.globl _tdata_begin
+_tdata_begin:
+
+.section ".tdata.end"
+.globl _tdata_end
+_tdata_end:
+
+.section ".tbss.end"
+.globl _tbss_end
+_tbss_end:
- lui a0, %hi(trap_entry)
- add a0, a0, %lo(trap_entry)
- mtpcr a0, evec
-
- lui a0, %hi(main)
- add a0, a0, %lo(main)
- mtpcr a0, epc
-
- # only allow core 0 to proceed
-1:mfpcr a0, hartid
- bnez a0, 1b
-
- la sp,stacktop
-
- # jmp to main as a user program
- eret
-1:b 1b
-
-.align 4
-.globl trap_entry
-trap_entry: # only check for SYS_exit, otherwise crash out
- li a3, 1337 # magic "bad things" happened error code
- mfpcr a1, cause
- li a2, 6 # syscall exception number
- bne a1, a2, exit_error
-handle_syscall:
- li a1, 93 # SYS_exit number
- bne v0, a1, exit_error
- li a1, 1 # successful exit code
- move a3, a0
- bne a3, a1, exit_error
- mtpcr a1, tohost # exit successfully (tohost == 1)
-1:b 1b
-exit_error:
- sll a3, a3, 1
- or a3, a3, 1
- mtpcr a3, tohost
-1:b 1b
-
- .bss
- .globl stacktop
-
- .align 4
- .skip 131072
-stacktop:
+.section ".tohost","aw",@progbits
+.align 6
+.globl tohost
+tohost: .dword 0
+.align 6
+.globl fromhost
+fromhost: .dword 0
projects / riscv-tests.git / blobdiff