Add read machine code

1 files changed, 85 insertions, 48 deletions

diff --git a/read.s b/read.s
index 7a5975d..9b4e382 100644
--- a/read.s
+++ b/read.s
@@ -1,64 +1,101 @@
 read:
-MOV #7000, R5     ; move read buffer address into R5
-; populate read buffer with console input until enter key is pressed
-; filter out bad characters here.
-; increment R5 along the way.
-; and start with null byte.
-; what we are left with is just (, ), A-Z, and space
-JSR PC, #parse_sexp
-JMP #eval
+002000 012705 MOV #7000, R5     ; move read buffer address into R5
+002002 007000
+002004 105025 CLRB (R5)+        ; move null byte into buffer
+loop:
+002006 032737 BIT #000200, @#177560
+002010 000200
+002012 177560
+002014 001774 BEQ loop          ; loop until char ready
+002016 113701 MOVB @#177562, R1
+002020 120127 CMPB R1, "\n"     ; done if enter was pressed
+002022 000012
+002024 001422 BEQ done
+002026 120127 CMPB R1, " "      ; good if space
+002030 000040
+002032 001414 BEQ good
+002034 120127 CMPB R1, "("      ; good if left paren
+002036 000050
+002040 001411 BEQ good
+002042 120127 CMPB R1, ")"      ; good if right paren
+002044 000051
+002046 001406 BEQ good
+002050 120127 CMPB R1, "A"      ; bad if lower than A
+002052 000101
+002054 103405 BLO bad
+002056 120127 CMPB R1, "Z"      ; bad if higher than Z
+002060 000132
+002062 101002 BHI bad
+good:
+002064 110125 MOVB R1, (R5)+    ; move good char into buffer
+002066 000747 BR loop           ; keep getting chars
+bad:
+002070 000777 BR -2             ; infinite loop
+done:
+002072 000137 JMP #parse_sexp
+002074 002100
 
 ; R4 = sexps
-
 parse_sexp:
-JSR PC, #get_next       ; get a character
-CMPB R0, ")"
-BNE if_atom             ; if atom get the atom
+002100 004737 JSR PC, #get_next       ; get a character
+002102 002300
+002104 120027 CMPB R0, ")"
+002106 000051
+002110 001020 BNE if_atom             ; if atom get the atom
 ; otherwise (if list)
 ; get the list
 if_list:
-MOV "NIL", R4           ; sexps <- empty list
+002112 012704 MOV "NIL", R4           ; sexps <- empty list
+002114 005000
 loop:
-JSR PC, #get_next
-CMPB R0, "("
-BEQ done                ; if "(" return the accumulated list
+002116 004737 JSR PC, #get_next
+002120 002300
+002122 120027 CMPB R0, "("
+002124 000050
+002126 001407 BEQ done                ; if "(" return the accumulated list
 ; if anything else:
-MOV R4, -(SP)           ; push sexps
-JSR PC, #parse_sexp     ; arg1 <- parse sexp
-MOV (SP)+, R1           ; arg2 <- pop accum
-JSR PC, #cons           ; cons result onto accum
-MOV R0, R4              ; sexps <- result
-BR -???                 ; continue recognizing list
+002130 010446 MOV R4, -(SP)           ; push sexps
+002132 004737 JSR PC, #parse_sexp     ; arg1 <- parse sexp
+002134 012601 MOV (SP)+, R1           ; arg2 <- pop accum
+002136 004737 JSR PC, #cons           ; cons result onto accum
+002140 004400
+002142 010004 MOV R0, R4              ; sexps <- result
+002144 000764 BR loop                 ; continue recognizing list
 done:
-MOV R4, R0              ; result <- sexps
-RTS PC
+002146 010400 MOV R4, R0              ; result <- sexps
+002150 000207 RTS PC
 if_atom:
-MOVB "\0", -(SP)    ; push null byte to stack
+002152 105046 CLRB -(SP)    ; push null byte to stack
 loop:
-MOVB R0, -(SP)      ; push character to stack ;
-MOVB -(R5), R0      ; get another character
-CMPB R0, "A"        ;
-BLO done            ; done if lower than A
-CMPB R0, "Z"        ;
-BHI done            ; done if higher than Z
-BR -???             ; continue getting characters
+002154 110046 MOVB R0, -(SP)      ; push character to stack
+002156 114500 MOVB -(R5), R0      ; get another character
+002160 120027 CMPB R0, "A"        ;
+002162 000101
+002164 103404 BLO done            ; done if lower than A
+002166 120027 CMPB R0, "Z"        ;
+002170 000132
+002172 101001 BHI done            ; done if higher than Z
+002174 000767 BR loop             ; continue getting characters
 done:
-MOVB R0, (R5)+      ; put the non-letter back
-MOV @#10000, R2     ; get free pointer
-MOV R2, R0          ; result <- address of new atom
-MOV 3(R2), (R2)+    ; allocate atom tag and increment free pointer
-MOVB (SP)+, (R2)+   ; pop a char off the stack and into the heap ; increment the free pointer (by 1)
-BNE -4              ; if it wasn't null keep going
-TST (R2)+           ; align free pointer
-MOV R2, @#10000     ; store new free pointer
-RTS PC
-
+002176 110026 MOVB R0, (R5)+      ; put the non-letter back
+002200 013702 MOV @#10000, R2     ; get free pointer
+002202 010200 MOV R2, R0          ; result <- address of new atom
+002204 016222 MOV 3(R2), (R2)+    ; allocate atom tag and increment free pointer
+002206 000003
+loop:
+002210 112622 MOVB (SP)+, (R2)+   ; pop a char off the stack and into the heap
+                                  ; increment the free pointer (by 1)
+002212 001376 BNE loop            ; if it wasn't null keep going
+002214 005722 TST (R2)+           ; align free pointer
+002216 010237 MOV R2, @#10000     ; store new free pointer
+002230 000207 RTS PC
 get_next:
 loop:
-MOVB -(R5), R0 
-BEQ bad             ; if null byte, no more input, very bad
-CMPB R0, " "        ; check if space
-BEQ loop            ; skip space
-RTS PC              ; return the lexically-valid character
+002300 114500 MOVB -(R5), R0
+002302 001404 BEQ bad             ; if null byte, no more input, very bad
+002304 120027 CMPB R0, " "        ; check if space
+002306 000040
+002310 001773 BEQ loop            ; skip space
+002312 000207 RTS PC              ; return the lexically-valid character
 bad:
-BR -2               ; infinite loop
+002314 000777 BR -2               ; infinite loop