Add very rough sketch assembler

1 files changed, 77 insertions, 0 deletions

diff --git a/assembler/assemble.s b/assembler/assemble.s
new file mode 100644
index 0000000..96940ea
--- /dev/null
+++ b/assembler/assemble.s
@@ -0,0 +1,77 @@
+1yyyxxxx Imm         yyy = shift amount xxxx = bit-width
+00000001 Brackets
+0011yyyy Reg        yyyy = shift amount
+0100yyyy Reg
+
+MOVS 0x 00 00 88 38
+ADDS 0x 00 00 88 38
+SUBS 0x 00 00 88 38
+CMP  0x 00 00 33 30
+ANDS 0x 00 00 33 30
+ORRS 0x 00 00 33 30
+TST  0x 00 00 33 30
+LSLS 0x 00 E5 33 30
+LSRS 0x 00 E5 33 30
+RORS 0x 00 00 33 30
+LDR  0x E5 33 01 30
+LDRB 0x 36 33 01 30
+STR  0x E5 33 01 30
+STRB 0x 36 33 01 30
+B<c> 0x 00 00 00 88
+B    0x 00 00 00 8B
+BX   0x 00 00 00 43
+
+// R2 holds the whole word
+// R0 holds just the byte
+// R1 holds either 3 or 4
+more:
+  MOVS R0, 0xFF
+  ANDS R0, R2
+  MOVS R1, 0x80
+  TST R0, R1
+  BNE handle_imm // if IMM
+  MOVS R1, 0xF0
+  ANDS R1, R0
+  BEQ handle_brackets // if BRACKETS
+handle_reg:
+  LSRS R1, 4
+  MOVS R3, 0x0F
+  ANDS R0, R3
+  // R1 = 3 or 4
+  // R0 = shift amount
+  BL register
+  B done_stuff
+
+handle_imm:
+  BL octal
+  B done_stuff
+
+handle_brackets:
+  // expect bracket
+  // echo bracket
+  LSRS R2, 0x8
+  BEQ next_instr
+  Back
+  ...
+
+done_stuff:
+  LSRS R2, 0x4
+  BEQ done
+  MOVS R0, 0
+  ORRS R0, R9
+  BL uart_send // echo the comma (or bracket)
+expect:
+  BL get_char
+  MOVS R1, '  // space char
+  CMP R0, R1
+  BNE expect // keep trying if not space
+  BL uart_send // echo the space
+  B more
+done:
+  TST R8, R8 // R8 == whether we are in bracket or not
+  BEQ no_brackets
+  MOVS R0, ']
+  BL uart_send
+no_bracket:
+  // echo carriage return + newline
+  B next_instr