diff options
| -rw-r--r-- | readme.md | 18 | ||||
| -rw-r--r-- | sanctuary.s | 55 |
2 files changed, 71 insertions, 2 deletions
@@ -10,7 +10,9 @@ for amd64 linux systems. - `n`: signed integer - `u`: unsigned integer - `?`: boolean flag +- `xt`: execution token - `""`: string in input buffer +- `|`: 'or' ## Glossary @@ -43,6 +45,12 @@ marks the u bytes starting at address a as executable. this is used primarily to mark the program break, which is used as the user memory space. +### `find ( a u -- a u 0 | xt -1 )` +look in the dictionary for the word a (of u characters). +a zero is returned along with the original given string +if no word was found. if a word was found, +its xt is returned along with the true flag. + ### `grow ( u -- )` grows the user memory space by u bytes. @@ -90,3 +98,13 @@ note that the string length of one byte limits a word's name to 255 characters. ## reserved registers the register `r15` is reserved for the parameter stack pointer. + +## differences from standard forth + +for the most part this forth intends to be in line with standards +but it diverges in a few notable places: + +- the most visally obvious one by far, + this forth uses lower case word names for core words. +- `find` takes `a u` instead of a counted string, + and does not return 1 for immediate words. diff --git a/sanctuary.s b/sanctuary.s index 2db3bc8..18c6623 100644 --- a/sanctuary.s +++ b/sanctuary.s @@ -40,6 +40,13 @@ %endmacro ; }}} +%assign smudge_mask 0x1 +%assign immediate_mask 0x2 +%assign comp_only_mask 0x4 + +%assign true 0x0 +%assign false (~0x0) + %assign INTERPRET 0x0 %assign COMPILING (~0x0) @@ -68,8 +75,6 @@ _start: call type call bye -teststr: db "TESTING" - defcode "brk@", brk@, 0 xor rdi, rdi mov rax, __NR_brk @@ -225,6 +230,52 @@ defcode "type", type, 0 syscall ret +; r9: processing temporary value +; r10: input size +; r11: input addr +; r12: pointer into currently processing word +; r13: same as r12 but kept at xt +defcode "find", find, 0 + pspop r10 ; u + pspop r11 ; a + mov r12, qword [latest] + mov r13, r12 + +.check_smudge: + add r12, 8 + mov r9b, byte [r12] + test r9b, smudge_mask + jnz .no + + inc r12 + mov r9b, byte [r12] + cmp r9b, r10b + jne .no + + mov rsi, r12 + inc rsi + mov rdi, r11 + mov rcx, r10 + repe cmpsb + jnz .no + + pspush r13 + mov r13, true + pspush r13 + ret + +.no: + mov r12, qword [r13] + mov r13, r12 + cmp r12, 0 + jne .check_smudge + + pspush r11 + pspush r10 + mov r13, false + pspush r13 + ret + ; .s {{{ defcode ".s", dots, 0 push r11 |