diff options
Diffstat (limited to 'libguile/scm.h')
| -rw-r--r-- | libguile/scm.h | 78 |
1 files changed, 43 insertions, 35 deletions
diff --git a/libguile/scm.h b/libguile/scm.h index b4c605ec8..64984dfdf 100644 --- a/libguile/scm.h +++ b/libguile/scm.h @@ -420,43 +420,52 @@ typedef uintptr_t scm_t_bits; -/* Checking if a SCM variable holds an immediate or a heap object. This - check can either be performed by checking for tc3==000 or tc3==00x, - since for a SCM variable it is known that tc1==0. */ -#define SCM_IMP(x) (6 & SCM_UNPACK (x)) -#define SCM_NIMP(x) (!SCM_IMP (x)) -#define SCM_HEAP_OBJECT_P(x) (SCM_NIMP (x)) +/* Checking if a SCM variable holds a tagged heap object (thob). */ -/* Checking if a SCM variable holds an immediate integer: See numbers.h - for the definition of the following macros: SCM_I_FIXNUM_BIT, - SCM_MOST_POSITIVE_FIXNUM, SCM_I_INUMP, SCM_I_MAKINUM, SCM_I_INUM. */ +#define scm_thob_tag 0 +#define scm_thob_tag_mask 7 +#define scm_thob_tag_size 3 + +#define SCM_THOB_P(x) ((SCM_UNPACK (x) & scm_thob_tag_mask) == scm_thob_tag) + +#define scm_pair_tag 6 +#define scm_pair_tag_mask 15 +#define scm_pair_tag_size 4 /* Checking if a SCM variable holds a pair (for historical reasons, in - Guile also known as a cons-cell): This is done by first checking that - the SCM variable holds a heap object, and second, by checking that - tc1==0 holds for the SCM_CELL_TYPE of the SCM variable. */ -#define SCM_I_CONSP(x) (!SCM_IMP (x) && ((1 & SCM_CELL_TYPE (x)) == 0)) + Guile also known as a cons-cell). */ +#define SCM_I_CONSP(x) \ + ((SCM_UNPACK (x) & scm_pair_tag_mask) == scm_pair_tag) + +#define SCM_HEAP_OBJECT_P(x) (SCM_THOB_P (x) || SCM_I_CONSP (x)) -/* Definitions for tc2: */ +/* Definitions for immediate tags: */ -#define scm_tc2_int 2 +#define scm_itag_mask 15 +#define scm_itag_mask_size 4 +#define SCM_ITAG(x) (SCM_UNPACK (x) & scm_itag_mask) -/* Definitions for tc3: */ +#define scm_itags_thob 0: case 8 +#define scm_itags_fixnum 15 +#define scm_itags_pair 6 +#define scm_itags_imm24 14 + +#define scm_fixnum_tag 15 +#define scm_fixnum_tag_mask 15 +#define scm_fixnum_tag_size 4 -#define SCM_ITAG3(x) (7 & SCM_UNPACK (x)) -#define SCM_TYP3(x) (7 & SCM_CELL_TYPE (x)) -#define scm_tc3_cons 0 +/* Definitions for tc3: */ + #define scm_tc3_struct 1 -#define scm_tc3_int_1 (scm_tc2_int + 0) -#define scm_tc3_unused 3 -#define scm_tc3_imm24 4 -#define scm_tc3_tc7_1 5 -#define scm_tc3_int_2 (scm_tc2_int + 4) -#define scm_tc3_tc7_2 7 + + +/* Definitions for tc4: */ + +#define scm_tc4_imm24 14 /* Definitions for tc7: */ @@ -464,15 +473,14 @@ typedef uintptr_t scm_t_bits; #define SCM_ITAG7(x) (0x7f & SCM_UNPACK (x)) #define SCM_TYP7(x) (0x7f & SCM_CELL_TYPE (x)) #define SCM_HAS_HEAP_TYPE(x, type, tag) \ - (SCM_NIMP (x) && type (x) == (tag)) + (SCM_THOB_P (x) && type (x) == (tag)) #define SCM_HAS_TYP7(x, tag) (SCM_HAS_HEAP_TYPE (x, SCM_TYP7, tag)) /* These type codes form part of the ABI and cannot be changed in a - stable series. The low bits of each must have the tc3 of a heap - object type code (see above). If you do change them in a development - series, change them also in (system vm assembler) and (system base - types). Bonus points if you change the build to define these tag - values in only one place! */ + stable series. If you do change them in a development series, + change them also in (system vm assembler) and (system base types). + Bonus points if you change the build to define these tag values + in only one place! */ #define scm_tc7_symbol 0x05 #define scm_tc7_variable 0x07 @@ -520,10 +528,10 @@ typedef uintptr_t scm_t_bits; enum scm_tc8_tags { - scm_tc8_flag = scm_tc3_imm24 + 0x00, /* special objects ('flags') */ - scm_tc8_char = scm_tc3_imm24 + 0x08, /* characters */ - scm_tc8_unused_0 = scm_tc3_imm24 + 0x10, - scm_tc8_unused_1 = scm_tc3_imm24 + 0x18 + scm_tc8_flag = scm_tc4_imm24 + 0x00, /* special objects ('flags') */ + scm_tc8_char = scm_tc4_imm24 + 0x10, /* characters */ + scm_tc8_unused_0 = scm_tc4_imm24 + 0x20, + scm_tc8_unused_1 = scm_tc4_imm24 + 0x30 }; #define SCM_ITAG8(X) (SCM_UNPACK (X) & 0xff) |