Add the `add2, sub2, litr, lit2r` ops

1 files changed, 103 insertions, 109 deletions

diff --git a/src/uxn-core.s b/src/uxn-core.s
index 2e7a165..a9fc3f9 100644
--- a/src/uxn-core.s
+++ b/src/uxn-core.s
@@ -20,47 +20,13 @@ rst_ptr: .word rst
 .global io_ports
 io_ports: .space 256
 
-@
-@ r0 is our custom stack pointer
-@ r1 is the value we want to insert/extract
-@
-@ When the stack grows downwards:
-@    push {r1} == str r1, [sp, #-4]!
-@    pop  {r1} == ldr r1, [sp], #4
-@
-@ In our case the stack grow upwards:
-@
-@ 8bit:
-@    push {r1} == strb r1, [sp], #1
-@    pop  {r1} == ldrb r1, [sp, #-1]!
-@
-@ 32bit:
-@    push {r1} == str r1, [sp], #4
-@    pop  {r1} == ldr r1, [sp, #-4]!
-@
-
-.global uxn_init_asm
-uxn_init_asm:
-    @ DEBUG: Initialize the stack for testing purposes.
-    ldr  r0, wst_ptr
-    mov  r1, #4
-    strb r1, [r0], #1
-    sub  r1, r1, #1
-    strb r1, [r0], #1
-    sub  r1, r1, #1
-    strb r1, [r0], #1
-    sub  r1, r1, #1
-    strb r1, [r0], #1
-    adr  r1, wst_ptr
-    str  r0, [r1]
-    bx lr
-
 @ UXN evaluation function.
 @
 @   r0: PC pointer (argument is offset from RAM).
 @   r1: Stack pointer (wst/rst).
 @   r2: Ram ptr.
 @   r3-r7: Scratch registers.
+@
 .global uxn_eval_asm
 uxn_eval_asm:
     @ Initialization.
@@ -95,13 +61,13 @@ brk:
     b uxn_ret
 
 jci:
-    b uxn_ret
+    b uxn_decode
 
 jmi:
-    b uxn_ret
+    b uxn_decode
 
 jsi:
-    b uxn_ret
+    b uxn_decode
 
 litr:
     ldrb r3, [r0], #1
@@ -109,201 +75,229 @@ litr:
     b uxn_decode
 
 lit2r:
-    b uxn_ret
+    ldrb r3, [r0], #1
+    ldrb r4, [r0], #1
+    strb r3, [r1], #1
+    strb r4, [r1], #1
+    b uxn_decode
 
 inc:
-    b uxn_ret
+    b uxn_decode
 
 inc2:
-    b uxn_ret
+    b uxn_decode
 
 pop:
-    b uxn_ret
+    b uxn_decode
 
 pop2:
-    b uxn_ret
+    b uxn_decode
 
 nip:
-    b uxn_ret
+    b uxn_decode
 
 nip2:
-    b uxn_ret
+    b uxn_decode
 
 swp:
-    b uxn_ret
+    b uxn_decode
 
 swp2:
-    b uxn_ret
+    b uxn_decode
 
 rot:
-    b uxn_ret
+    b uxn_decode
 
 rot2:
-    b uxn_ret
+    b uxn_decode
 
 dup:
-    b uxn_ret
+    b uxn_decode
 
 dup2:
-    b uxn_ret
+    b uxn_decode
 
 ovr:
-    b uxn_ret
+    b uxn_decode
 
 ovr2:
-    b uxn_ret
+    b uxn_decode
 
 equ:
-    b uxn_ret
+    b uxn_decode
 
 equ2:
-    b uxn_ret
+    b uxn_decode
 
 neq:
-    b uxn_ret
+    b uxn_decode
 
 neq2:
-    b uxn_ret
+    b uxn_decode
 
 gth:
-    b uxn_ret
+    b uxn_decode
 
 gth2:
-    b uxn_ret
+    b uxn_decode
 
 lth:
-    b uxn_ret
+    b uxn_decode
 
 lth2:
-    b uxn_ret
+    b uxn_decode
 
 jmp:
-    b uxn_ret
+    b uxn_decode
 
 jmp2:
-    b uxn_ret
+    b uxn_decode
 
 jcn:
-    b uxn_ret
+    b uxn_decode
 
 jcn2:
-    b uxn_ret
+    b uxn_decode
 
 jsr:
-    b uxn_ret
+    b uxn_decode
 
 jsr2:
-    b uxn_ret
+    b uxn_decode
 
 sth:
-    b uxn_ret
+    b uxn_decode
 
 sth2:
-    b uxn_ret
+    b uxn_decode
 
 ldz:
-    b uxn_ret
+    b uxn_decode
 
 ldz2:
-    b uxn_ret
+    b uxn_decode
 
 stz:
-    b uxn_ret
+    b uxn_decode
 
 stz2:
-    b uxn_ret
+    b uxn_decode
 
 ldr:
-    b uxn_ret
+    b uxn_decode
 
 ldr2:
-    b uxn_ret
+    b uxn_decode
 
 str:
-    b uxn_ret
+    b uxn_decode
 
 str2:
-    b uxn_ret
+    b uxn_decode
 
 lda:
-    b uxn_ret
+    b uxn_decode
 
 lda2:
-    b uxn_ret
+    b uxn_decode
 
 sta:
-    b uxn_ret
+    b uxn_decode
 
 sta2:
-    b uxn_ret
+    b uxn_decode
 
 dei:
-    b uxn_ret
+    b uxn_decode
 
 dei2:
-    b uxn_ret
+    b uxn_decode
 
 deo:
-    b uxn_ret
+    b uxn_decode
 
 deo2:
-    b uxn_ret
+    b uxn_decode
 
 add:
-    ldr r3, [r1, #-1]!
-    ldr r4, [r1, #-1]!
-    add r3, r3, r4
+    ldr  r3, [r1, #-1]!
+    ldr  r4, [r1, #-1]!
+    add  r3, r3, r4
     strb r3, [r1], #1
-    b uxn_ret @ NOTE: This should return to the next loop iteration.
+    b uxn_decode
 
 add2:
-    b uxn_ret
+    ldrb r3, [r1, #-1]!
+    lsl  r3, #8
+    ldrb r5, [r1, #-1]!
+    add  r3, r5
+    ldrb r4, [r1, #-1]!
+    ldrb r5, [r1, #-1]!
+    lsl  r4, #8
+    add  r4, r5
+    add  r3, r3, r4
+    strb r3, [r1], #1
+    lsr  r3, #8
+    strb r3, [r1], #1
+    b uxn_decode
 
 sub:
-    @ ldr r2, [r0, #-1]!
-    @ ldr r1, [r0, #-1]!
-    @ sub r1, r1, r2
-    @ strb r1, [r0], #1
-    b uxn_ret @ NOTE: This should return to the next loop iteration.
+    ldr  r3, [r1, #-1]!
+    ldr  r4, [r1, #-1]!
+    sub  r4, r4, r3
+    strb r4, [r1], #1
+    b uxn_decode
 
 sub2:
-    b uxn_ret
+    ldrb r3, [r1, #-1]!
+    ldrb r5, [r1, #-1]!
+    lsl  r3, #8
+    add  r3, r5
+    ldrb r4, [r1, #-1]!
+    ldrb r5, [r1, #-1]!
+    lsl  r4, #8
+    add  r4, r5
+    sub  r3, r4, r3
+    strb r3, [r1], #1
+    lsr  r3, #8
+    strb r3, [r1], #1
+    b uxn_decode
 
 mul:
-    b uxn_ret
+    b uxn_decode
 
 mul2:
-    b uxn_ret
+    b uxn_decode
 
 div:
-    b uxn_ret
+    b uxn_decode
 
 div2:
-    b uxn_ret
+    b uxn_decode
 
 and:
-    b uxn_ret
+    b uxn_decode
 
 and2:
-    b uxn_ret
+    b uxn_decode
 
 ora:
-    b uxn_ret
+    b uxn_decode
 
 ora2:
-    b uxn_ret
+    b uxn_decode
 
 eor:
-    b uxn_ret
+    b uxn_decode
 
 eor2:
-    b uxn_ret
+    b uxn_decode
 
 sft:
-    b uxn_ret
+    b uxn_decode
 
 sft2:
-    b uxn_ret
+    b uxn_decode
 
 @ OP table
 op_table:
@@ -468,7 +462,7 @@ op_table:
     .word brk    @ 0x9d
     .word brk    @ 0x9e
     .word brk    @ 0x9f
-    .word brk    @ 0xa0
+    .word lit2r  @ 0xa0
     .word brk    @ 0xa1
     .word brk    @ 0xa2
     .word brk    @ 0xa3