From 6a031fb49d595726da16adcf868475b1e104d60d Mon Sep 17 00:00:00 2001
From: Julian Blake Kongslie
Date: Sun, 4 Apr 2021 16:20:24 -0700
Subject: Remove idx, add indirect jumps, renumber opcodes so NOP=0, add
 absolute labels to asm.rb

---
 mem/mem.hex | 154 +++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 84 insertions(+), 70 deletions(-)

(limited to 'mem/mem.hex')

diff --git a/mem/mem.hex b/mem/mem.hex
index 07023a8..4d5700f 100644
--- a/mem/mem.hex
+++ b/mem/mem.hex
@@ -1,76 +1,90 @@
 @0
 
-// Reset state is acc=0 idx=0
+10d // acc= @fib       # for the toy indirect jump to fib
+369 // store 0x69
+170 // acc= 0x70
+36a // store 0x6a
+001 // loop: cla
+2ea // ladd i 0x6a
+400 // ifeq 0
+5e9 // jmp i 0x69       # toy indirect jump to fib
+040 // tx
+003 // cla ++acc
+26a // ladd 0x6a
+36a // store 0x6a
+577 // jmp loop
+36a // fib: store 0x6a  # zero, it is known
+370 // store 0x70       # 0x70 is now beginning of Fibonacci sequence (0)
+003 // cla ++acc
+371 // store 0x71       # 0x71 is 1
+170 // fibloop: acc= 0x70
+26a // ladd 0x6a
+369 // store 0x69
+001 // cla
+2e9 // ladd i 0x69      # next fib number to print
+66b // ascii 0x6b       # LSB of ASCII rep
+66c // ascii 0x6c
+66d // ascii 0x6d
+66e // ascii 0x6e       # MSB of ASCII rep
+104 // acc= 4
+369 // store 0x69
+005 // scan: cla --acc
+269 // ladd 0x69
+4ff // ifeq -1
+508 // jmp print
+369 // store 0x69
+16b // acc= 0x6b
+269 // ladd 0x69
+368 // store 0x68
+001 // cla
+2e8 // ladd i 0x68
+430 // ifeq 0x30
+574 // jmp scan
+16b // print: acc= 0x6b
+269 // ladd 0x69
+368 // store 0x68
+001 // cla
+2e8 // ladd i 0x68
+040 // tx
+005 // cla --acc
+269 // ladd 0x69
+4ff // ifeq -1
+502 // jmp space
+369 // store 0x69
+574 // jmp print
+120 // space: acc= 0x20
+040 // tx
+170 // acc= 0x70
+26a // ladd 0x6a
+369 // store 0x69
+003 // cla ++acc
+269 // ladd 0x69        # compute &fib[i+1]
+368 // store 0x68
+003 // cla ++acc
+268 // ladd 0x68        # compute &fib[i+2]
+367 // store 0x67
+001 // cla
+2e9 // ladd i 0x69
+2e8 // ladd i 0x68      # compute fib[i+2]
+3e7 // store i 0x67     # store it
+003 // cla ++acc
+26a // ladd 0x6a
+432 // ifeq 50
+502 // jmp fullydone
+36a // store 0x6a
+548 // jmp fibloop
+121 // fullydone: acc= 0x21
+040 // tx
+080 // halt
 
-000 // loop: acc= 0     # Print from 0x70 until we find a 0x00 byte
-170 // ladd i 0x6a
-300 // ifeq 0
-402 // jmp fib
-f44 // ++idx tx
-4fa // jmp loop
-f20 // fib: idx         # N.B. acc is 0 at this point (we got here from ifeq 0)
-270 // store 0x70       # 0x70 is now beginning of Fibonacci sequence (0)
-001 // acc= 1
-271 // store 0x71       # 0x71 is 1
-000 // fibloop: acc= 0
-f10 // swap
-332 // ifeq 50
-42b // jmp fullydone
-26f // store 0x6f       # 0x6f is current index into Fibonacci sequence
-f10 // swap
-170 // ladd 0x70        # Load next unprinted number in Fibonacci sequence
-f10 // swap
-000 // acc= 0
-f10 // swap
-56b // ascii 0x6b       # LSB of ASCII rep
-56c // ascii 0x6c
-56d // ascii 0x6d
-56e // ascii 0x6e       # MSB of ASCII rep
-004 // acc= 4
-f10 // swap
-f08 // scan: --idx
-000 // acc= 0
-16b // ladd 0x6b
-f10 // swap
-300 // ifeq 0
-412 // jmp allzeroes
-f10 // swap
-330 // ifeq 0x30
-4f7 // jmp scan
-f40 // done: tx
-f10 // swap
-300 // ifeq 0
-404 // jmp space
-f12 // --acc swap
-000 // acc= 0
-16b // ladd 0x6b
-4f8 // jmp done
-020 // space: acc= 0x20
-f40 // tx
-000 // acc= 0
-f20 // idx
-16f // ladd 0x6f
-f10 // swap
-402 // jmp nextfib
-f10 // allzeroes: swap
-4ef // jmp done
-170 // nextfib: ladd 0x70   # Load just-printed Fibonacci number
-171 // ladd 0x71            # Add about-to-print Fibonacci number
-272 // store 0x72           # Store n+2 Fibonacci number
-f04 // ++idx
-4d1 // jmp fibloop
-021 // fullydone: acc= 0x21
-f40 // tx
-f80 // halt
-
-@6a
-
-070 // 6a: constant 0x070
-000 // 6b: LSB of ASCII rep
-000 // 6c: USB of ASCII rep
-000 // 6d: USB of ASCII rep
-000 // 6e: MSB of ASCII rep
-000 // 6f: next index to store in memory image of Fibonacci sequence
+// 67: scratch (pointer to fib[i+2])
+// 68: scratch (pointer to fib[i+1])
+// 69: scratch (pointer to fib[i]) (j)
+// 6a: i
+// 6b: LSB of ASCII rep
+// 6c: USB of ASCII rep
+// 6d: USB of ASCII rep
+// 6e: MSB of ASCII rep
 
 @70
 
-- 
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