* Helpers:
Using the tcg_gen_helper_x_y it is possible to call any function
-taking i32, i64 or pointer types. Before calling an helper, all
-globals are stored at their canonical location and it is assumed that
-the function can modify them. In the future, function modifiers will
-be allowed to tell that the helper does not read or write some globals.
+taking i32, i64 or pointer types. By default, before calling an helper,
+all globals are stored at their canonical location and it is assumed
+that the function can modify them. This can be overriden by the
+TCG_CALL_CONST function modifier. By default, the helper is allowed to
+modify the CPU state or raise an exception. This can be overriden by
+the TCG_CALL_PURE function modifier, in which case the call to the
+function is removed if the return value is not used.
On some TCG targets (e.g. x86), several calling conventions are
supported.
* eqv_i32/i64 t0, t1, t2
-t0=~(t1^t2)
+t0=~(t1^t2), or equivalently, t0=t1^~t2
* nand_i32/i64 t0, t1, t2
* bswap16_i32/i64 t0, t1
-16 bit byte swap on a 32/64 bit value. The two/six high order bytes must be
-set to zero.
+16 bit byte swap on a 32/64 bit value. It assumes that the two/six high order
+bytes are set to zero.
* bswap32_i32/i64 t0, t1
-32 bit byte swap on a 32/64 bit value. With a 64 bit value, the four high
-order bytes must be set to zero.
+32 bit byte swap on a 32/64 bit value. With a 64 bit value, it assumes that
+the four high order bytes are set to zero.
* bswap64_i64 t0, t1
Indicate that the value of t0 won't be used later. It is useful to
force dead code elimination.
+********* Conditional moves
+
+* setcond_i32/i64 cond, dest, t1, t2
+
+dest = (t1 cond t2)
+
+Set DEST to 1 if (T1 cond T2) is true, otherwise set to 0.
+
********* Type conversions
* ext_i32_i64 t0, t1
Similar to mul, except two 32-bit (unsigned) inputs T1 and T2 yielding
the full 64-bit product T0. The later is returned in two 32-bit outputs.
+* setcond2_i32 cond, dest, t1_low, t1_high, t2_low, t2_high
+
+Similar to setcond, except that the 64-bit values T1 and T2 are
+formed from two 32-bit arguments. The result is a 32-bit value.
+
********* QEMU specific operations
* tb_exit t0
qemu_ld8s t0, t1, flags
qemu_ld16u t0, t1, flags
qemu_ld16s t0, t1, flags
+qemu_ld32 t0, t1, flags
qemu_ld32u t0, t1, flags
qemu_ld32s t0, t1, flags
qemu_ld64 t0, t1, flags
-Load data at the QEMU CPU address t1 into t0. t1 has the QEMU CPU
-address type. 'flags' contains the QEMU memory index (selects user or
-kernel access) for example.
+Load data at the QEMU CPU address t1 into t0. t1 has the QEMU CPU address
+type. 'flags' contains the QEMU memory index (selects user or kernel access)
+for example.
+
+Note that "qemu_ld32" implies a 32-bit result, while "qemu_ld32u" and
+"qemu_ld32s" imply a 64-bit result appropriately extended from 32 bits.
* qemu_st8 t0, t1, flags
qemu_st16 t0, t1, flags