1 files changed, 104 insertions, 0 deletions
diff --git a/examples/ask_name.subv b/examples/ask_name.subv
new file mode 100644
index 0000000..b9e54bc
--- /dev/null
+++ b/examples/ask_name.subv
@@ -0,0 +1,104 @@
+# ask for the user's name,
+# then print it back with a hello message.
+#
+# until I figure out how to enable STDIN properly,
+# requires running qemu like so:
+#
+# $ ./subv.sh examples/ask_.subv >examples/ask_.elf
+# $ cat 2>dev/null | ./qemu.sh examples/ask_.elf
+#   What's your name?
+# > Sol
+#   Hello Sol, nice to meet you!
+
+== code 0x80000000
+  # trap all but first Hart (a0 = mhartid)
+  63/branch 1/subop/!= a/rs/a0 0/rs/x0 0/off13
+
+main:
+  # print HELLO_WHATSURNAME
+  37/lui a/rd/a0 HELLO_WHATSURNAME/imm20hi
+  13/opi 0/subop/add a/rd/a0 a/rs/a0 HELLO_WHATSURNAME/imm12lo
+  6f/jal 1/rd/ra print/off21
+
+  37/lui a/rd/a0 Name/imm20hi
+  13/opi 0/subop/add a/rd/a0 a/rs/a0 Name/imm12lo
+  6f/jal 1/rd/ra read/off21
+
+  # print HELLO_
+  37/lui a/rd/a0 HELLO_/imm20hi
+  13/opi 0/subop/add a/rd/a0 a/rs/a0 HELLO_/imm12lo
+  6f/jal 1/rd/ra print/off21
+
+  # print Name
+  37/lui a/rd/a0 Name/imm20hi
+  13/opi 0/subop/add a/rd/a0 a/rs/a0 Name/imm12lo
+  6f/jal 1/rd/ra print/off21
+
+  # print NICETOMEETU
+  37/lui a/rd/a0 NICETOMEETU/imm20hi
+  13/opi 0/subop/add a/rd/a0 a/rs/a0 NICETOMEETU/imm12lo
+  6f/jal 1/rd/ra print/off21
+
+  # infinite loop
+  6f/jal 0/rd/x0 0/off21
+
+print:
+# print a C-string from a0
+  # load 0x10010000 (UART0) into t0
+  37/lui 5/rd/t0 0x10010/imm20
+print:loop:
+  # load unsigned byte at x4
+  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 (t2 sign bit is set)
+  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/width/word 5/rs/t0 6/rs/t1 0/off12
+  # increment a0
+  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
+
+read:
+# read a C-string into a0
+  # load 0x10010004 (UART0+4) into t0
+  37/lui 5/rd/t0 0x10010/imm20
+  13/opi 0/subop/add 5/rd/t0 5/rs/t0 4/imm12
+  # load 0x0a (\n) into t1
+  13/opi 0/subop/add 6/rd/t1 0/rs/x0 0a/imm12
+read:loop:
+  # load word at a0 into t0
+  03/load 2/subop/word 7/rd/t2 5/rs/t0 0/imm12
+  # spin if FIFO is empty (t2 sign bit is set)
+  63/branch 4/subop/< 7/rs/t2 0/rs/x0 read:loop/off13
+  # break loop if newline (t2 == t1)
+  63/branch 0/subop/== 7/rs/t2 6/rs/t1 read:break/off13
+  # store char at a0
+  23/store 2/width/word a/rs/a0 7/rs/t2 0/off12
+  # increment a0
+  13/opi 0/subop/add a/rd/a0 a/rs/a0 1/imm12
+  # jump back up
+  6f/jal 0/rd/x0 read:loop/off21
+read:break:
+  # return
+  67/jalr 0/subop 0/rd/x0 1/rs/ra 0/off12
+
+
+== data 0x80500000
+HELLO_WHATSURNAME:
+  # "What's your name?\n\0"
+  57/8 68/8 61/8 74/8 27/8 73/8 20/8 79/8 6f/8 75/8 72/8 20/8 6e/8 61/8 6d/8 65/8 3f/8 0a/8 00/8
+HELLO_:
+  # "Hello \0"
+  48/8 65/8 6c/8 6c/8 6f/8 20/8 00/8
+NICETOMEETU:
+  # ", nice to meet you!\n\0"
+  2c/8 20/8 6e/8 69/8 63/8 65/8 20/8 74/8 6f/8 20/8 6d/8 65/8 65/8 74/8 20/8 79/8 6f/8 75/8 21/8 0a/8 00/8
+Name:
+  00/8