1 files changed, 62 insertions, 0 deletions
diff --git a/assembly/multiplatform/multiplatform.S b/assembly/multiplatform/multiplatform.S
new file mode 100644
index 0000000..2c564e4
--- /dev/null
+++ b/assembly/multiplatform/multiplatform.S
@@ -0,0 +1,62 @@
+_start:
+# Determine RV32/RV64
+li t0,2
+slli t0,t0,31 # This shift is out of bounds on RV32 but not RV64
+bnez t0,is_rv64
+
+# Detect R4
+div t0,zero,zero # div works on RVController but is decoded as mul by R4
+beqz t0,is_r4 # R4 outputs 0*0 = 0
+j is_rvcontroller # RVController outputs 0/0 = -1
+
+is_rv64:
+# RV64 platform of some sort, only supported one of those is Linux, output message to stdout
+li a7,0x40 # write()
+li a0,1 # stdout
+la a1,linux_message
+li a2,13 # count
+ecall
+
+li a7,0x5d # exit
+li a0,0 # return code
+ecall
+
+is_r4:
+li t0,0x10000014 # terminal color
+li t1,0xF # white on black
+sw t1,0(t0)
+
+li t0,0x10000004 # terminal hrange
+li t1,0x160 # 0-11
+sw t1,0(t0)
+
+li t0,0x10000008 # terminal vrange
+li t1,0xe0 # 0-7
+sw t1,0(t0)
+
+li t0,0x10000204 # terminal scrollprint
+la t2,r4_message
+loop:
+lb t1,0(t2) # read a character of the message
+beqz t1,done # check for end
+sw t1,0(t0) # print it
+addi t2,t2,1 # next character
+j loop
+
+done:
+ebreak
+
+
+is_rvcontroller:
+# RVController, output message to stdout
+li a7,4 # Print string
+la a0,rvc_message
+ecall
+li a7,10 # Exit program
+ecall
+
+linux_message: .ascii "Hello Linux!\n"
+r4_message: .asciz "Hello R4!"
+rvc_message: .asciz "Hello RVController!"
+
+.globl _start