From cd70703964b5f58de4071b1bd9f18cee34150aca Mon Sep 17 00:00:00 2001
From: Ketmar Dark <ketmar@ketmar.no-ip.org>
Date: Sat, 15 Aug 2020 03:05:09 +0300
Subject: [PATCH] fixed bugs in expression evaluator

---
 main.zas        |  4 ++++
 parser_expr.zas | 48 +++++++++++++++++++++++++++---------------------
 2 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/main.zas b/main.zas
index 6059dca..b43e48f 100644
--- a/main.zas
+++ b/main.zas
@@ -174,9 +174,13 @@ errline: defx "---------"
 
 
 strbuf:
+  defm  "ld   e,420%10",13
   defm  "label cp  69",13
   ;defm  "jr   label",13
   defm  "ld   a,40+2",13
+  defm  "ld   b,44-2",13
+  defm  "ld   c,126/3",13
+  defm  "ld   e,427%10",13
   defm  "ld   bc,2+3*5",13
   defm  "ld   bc,0+(2+3)*5",13
   defm  "ld   bc,[2+3]*5",13
diff --git a/parser_expr.zas b/parser_expr.zas
index 8e92c76..82281b7 100644
--- a/parser_expr.zas
+++ b/parser_expr.zas
@@ -101,13 +101,9 @@ PARSE_INT_EXPR:
   ret   nz
 .doshift:
   ; get second operand
-  push  hl
-  push  af      ; A holds operation
-  inc   iy      ; skip operation
-  inc   iy      ; skip operation
-  call  .addsub
-  pop   af
-  pop   de
+  inc   iy      ; skip operation part
+  ld    bc,.addsub
+  call  .go_down_bc
   ld    c,a
   ; HL: number to shift
   ; DE: amount
@@ -151,12 +147,8 @@ PARSE_INT_EXPR:
   ret   nz
 .doaddsub:
   ; get second operand
-  push  hl
-  push  af      ; A holds operation
-  inc   iy      ; skip operation
-  call  .muldiv
-  pop   af
-  pop   de
+  ld    bc,.muldiv
+  call  .go_down_bc
   bit   1,a
   jr    z,.dosub
   add   hl,de
@@ -182,12 +174,9 @@ PARSE_INT_EXPR:
   ret   nz
 .domuldiv:
   ; get second operand
-  push  hl
-  push  af      ; A holds operation
-  inc   iy      ; skip operation
-  call  .term
-  pop   af
-  pop   de
+  ld    bc,.term
+  call  .go_down_bc
+  ld    bc,hl
   bit   2,a
   jr    z,.domul
   ex    af,af'  ; save operation
@@ -195,7 +184,6 @@ PARSE_INT_EXPR:
   ld    a,e
   or    d
   jp    z,PARSE_EXPR_ERROR_0DIV
-  ld    bc,hl
   call  PARSER_UDIV_BC_DE
   ; was it div or mod?
   ex    af,af'
@@ -205,7 +193,6 @@ PARSE_INT_EXPR:
   ld    hl,bc
   jr    .muldiv_next
 .domul:
-  ld    bc,hl
   call  PARSER_UMUL_BC_DE
   jr    .muldiv_next
 
@@ -253,6 +240,25 @@ PARSE_INT_EXPR:
   ld    l,a
   ret
 
+  ;; call subroutine at BC
+  ;; AF: preserved
+  ;; HL: preserved
+  ;; DE: subroutine result
+  ;; i.e. HL is op0, DE is op1
+.go_down_bc:
+  push  hl
+  push  af      ; A holds operation
+  inc   iy      ; skip operation
+  ld    hl,.go_down_bc_ret
+  push  hl
+  push  bc
+  ret
+.go_down_bc_ret:
+  pop   af
+  pop   de
+  ex    de,hl
+  ret
+
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;
-- 
2.11.4.GIT