good helloworld example

1 files changed, 26 insertions, 14 deletions

diff --git a/test.subv b/test.subv
index aa7d010..60d9065 100644
--- a/test.subv
+++ b/test.subv
@@ -1,31 +1,43 @@
 == code 0x80000000
-main:
-  # load 0x10010000 (UART0) into t0
-  37/lui 5/rd/t0 0x10010/imm20
+  # load mhartid CSR into t0, trap all but first Hart
+  73/system 5/rd/t0 2/funct3/csrrs 0/rs/x0 f14/imm12/mhartid 
+  63/branch 1/subop/!= 5/rs/t0 0/rs/x0 0/off13
 
+main:
   # x4 = &message
   # . load high bits
-  37/lui 4/rd/x4 Message/imm
+  37/lui a/rd/a0 Message/imm20hi
   # . add low bits
-  13/opi 0/subop/add 4/rd/x4 4/rs/x4 Message/imm
+  13/opi 0/subop/add 4/rd/x4 a/rs/a0 Message/imm12lo
+  # call print
+  6f/jal 1/rd/ra print/off21
+loop:
+  # infinite loop
+  6f/jal 0/rd/x0 loop/off21
+
+print:
+  # load 0x10010000 (UART0) into t0
+  37/lui 5/rd/t0 0x10010/imm20
 print:loop:
   # load unsigned byte at x4
-  03/load 4/subop/lbu 6/rd/t1 4/rs/x4 0/imm12
+  03/load 4/subop/byte 6/rd/t1 a/rs/a0 0/imm12
   # break loop if zero
   63/branch 0/subop/== 6/rs/t1 0/rs/x0 print:break/off13
+print:spin:
+  # spin if FIFO is full
+  03/load 2/subop/word 7/rd/t2 5/rs/t0 0/imm12
+  63/branch 4/subop/< 7/rs/t2 0/rs/x0 print:spin/off13
   # print char
-  23/store 2/subop/word 5/rs/t0 6/rs/t1 0/off12
+  23/store 2/width/word 5/rs/t0 6/rs/t1 0/off12
   # increment x4
-  13/opi 0/subop/add 4/rd/x4 4/rs/x4 1/imm12
+  13/opi 0/subop/add a/rd/a0 a/rs/a0 1/imm12
   # jump back up
   6f/jal 0/rd/x0 print:loop/off21
 print:break:
+  # return
+  67/jalr 0/subop 0/rd/x0 1/rs/ra 0/off12
 
-loop:
-  # infinite loop
-  6f/jal 0/rd/x0 loop/off21
-
-== data 0x80001000
+== data 0x80500000
 Message:
-  # "Hello World\n\0"
+  # "Hello World!\n\0"
   48/8 65/8 6c/8 6c/8 6f/8 20/8 77/8 6f/8 72/8 6c/8 64/8 21/8 0a/8 00/8