Change word layout to more wasteful use of full cells.

Also added cross-pointers to simplify moving between tfa and cfa.

diff --git a/machine.asm b/machine.asm
index a8bfbd8f7652985a63836f81a38165211ec5efbb..74b1060427dbce1cfc4321e405ae19f8e2484f1b 100644 (file)
--- a/machine.asm
+++ b/machine.asm
@@ -103,30 +103,49 @@ macro DOFORTH label {
        ENDFORTH
 }
 
-;;; ========================================
-;;; Macro WORD starts a FORTH word definition in this code
-;;; 
        previous_word = 0       ; Used for chaining the words
 
        IMMEDIATE = 1           ; optional flag (symbol)
 
-macro WORD label, name, doer, flags {
+;;; ========================================
+;;; Macro WORD starts a FORTH word definition in this code.
+;;; The layout of a word is as follows:
+;;; TFA: [8 bytes] pointer to previous word in the word list
+;;;      [8 bytes] pointer to the word's CFA
+;;;      [8 bytes] a flags field
+;;;      [8 bytes] the length of the word's pname
+;;;      [varying] the word's pname
+;;;      [1 byte]  NUL -- making an asciiz of the pname
+;;;      ;;[? bytes] 0-7 bytes for address alignment to [disabled]
+;;;      [8 bytes] pointer to the word's TFA
+;;; OFF: [8 bytes] the DOES offset for the word
+;;; CFA: [8 bytes] pointer to the word's "doer" code
+;;; DFA: [? bytes] the word's data field
+
+macro WORD label, name, doer, flags, previous, offset {
+       local pname
        ;; align 8
 label#_TFA:
        ;; TFA
-       dq previous_word
+       if previous eq
+           dq previous_word
+       else
+           dq previous
+       end if
        previous_word = label#_TFA
        ;; PFA
+       dq label#_CFA           ; link to CFA of word
+       dq flags + 0
 label#_PFA:
-       db flags + 0
-       db label - $ - 2
+       dq pname - $ - 8
        db name
-       db 0
+pname:  db 0                   ; extra NUL byte
        ;; align 8
-
+       dq label#_TFA           ; link to TFA of word
 label#_OFF:
-       dq 0                    ; The DOES offset. Defaults to 0.
+       dq offset + 0           ; The DOES offset. Defaults to 0.
        ;; also CFA = pointer to "doer"
+label#_CFA:
 label:
        if doer eq
            dq doforth
@@ -141,6 +160,39 @@ label:
 label#_DFA:
 }
 
+macro tfa2cfa reg {
+       mov reg,qword [reg+8]
+}
+macro tfa2dfa reg {
+       tfa2cfa reg
+       add reg,8
+}
+macro tfa2pfa reg {
+       add reg,24
+}
+macro tfa2pname reg {
+       add reg,32
+}
+macro cfa2tfa reg {
+       sub reg,16
+       mov reg,qword [reg]
+}
+macro cfa2dfa reg {
+       add reg,8
+}
+macro dfa2cfa reg {
+       sub reg,8
+}
+macro dfa2tfa reg {
+       sub reg,24
+       mov reg,qword [reg]
+}
+macro pushpname rg {   ; ( reg -- chars* length )
+       add rg,8
+       push rg
+       sub rg,8
+       push qword [rg]
+}
 ;;; ========================================
 ;;; The BLOCK macro lays out the length for a subsequent block to the
 ;;; given label.
@@ -151,11 +203,12 @@ datastart:
        }
 
 ;;; ========================================
-;;; The STRING macro lays out length byte and data for s short string
+;;; The STRING macro lays out length cell and data for several string
+;;; components.
 macro STRING [data] {
 common
        local datastart, dataend
-       db dataend - datastart
+       dq dataend - datastart
 datastart:
 forward
        db data